Oh boy! [rubs hands in glee at topic/question]
Short version: Either brand is extremely suitable for these purposes. The most important thing is figuring out which of the equipment divisions you want to play in, and then buying an appropriate model - but both makers have highly competitive and comparable offerings for each division where they are relevant.
Long version: Is long. You've been warned.
Practical shooting competition divides up into a few games, and each of those games divides the compeition within the game up by equipment division. You can think of divisions as being like the different car classes in a Le Mans race - everyone is running on the same track, but the prototype cars and the GT cars are not really competing, because the technical advantages of the proto's are so great that you have to look at results separately. An even more basic analogy would be weight classes in the fighting games (boxing/wrestling/MMA).
I'll talk about USPSA/IPSC because: 1) it's what I shoot and therefore know best; 2) it's larger and older than IDPA and the other offshoots; and 3) it's the best in terms of quality of competition and shooting demands. The last is only
slightly subjective.
USPSA rules and how they relate to your question
There are several equipment divisions in USPSA. A bunch of them - revolver, single-stack, pistol caliber carbine - are totally irrelevant to this discussion. Another one - Limited 10 - is totally irrelevant to anyone who doesn't live in a state like CA or MA where 11-round mags are illegal or hard to get in adequate quantities.
So what are the relevant divisions that you might be choosing between? There are 3, primarily, with a 4th that I will also mention: Production, Limited, Carry Optics, and (this is the 4th one) Open. I'll try to briefly describe each one and why you might want to shoot it (or not shoot it). Once you figure out which one is most likely to appeal to you, that will narrow down your choices on models significantly.
Production: Production requires use of DA/SA guns with the hammer down at the start of each stage (or a striker-fired gun) with iron sights only, and the guns have to come from a pre-approved list (it's a big list, but requires certain minimum volumes in the U.S. market and compliance with other specific rules). All guns are scored minor PF*, so the overwhelming majority of people shooting this division shoot 9mm. Magazines are limited to 10 rounds (you can use higher-capacity magazines, you just can't load more than 10 rounds). You have to have the holster and all magazines behind the front of the hip-bone (basically, 3 o'clock). This division emphasizes a lot of reloads (basically every time you move you're likely to be reloading), and puts a premium on accuracy due to the minor PF scoring. There are rules on what modifications can be done to the guns, but you can modify internals and hammers and triggers very liberally (but you've got to keep the gun DA/SA). You cannot add a magwell. You cannot add a thumbrest (although there's currently a rule interpretation that allows slide stops that has an integral thumb ledge to be allowed - which interpretation may or may not stay in place). The guns used generally still look at least a little like service-type guns.
Limited: Limited allows SAO guns (or DA/SA guns cocked-and-locked at the start, or striker-fired guns) with iron sights only. Magazines are unlimited in capacity, but limited to 141mm in length (usually getting +4 to +6 capacity versus flush magazines with a shallow follower). Compensators/ports are prohibited. Other than that, shoot pretty much whatever you like. This division recognizes major scoring, but requires a .400/.10mm bullet in addition to the 165 PF. For this reason, almost everyone serious about this division shoots .40 cal. 45 doesn't give you any scoring advantage and kills magazine capacity, so nobody shoots that. 9mm won't let you get major scoring, which is generally not worth the tradeoff to get an extra 2-3 rounds. There are a few people who are so accurate that they are able to compete heads-up with minor scoring, but it is not advantageous. Stage times in this division will be faster than in Production, and refining sight pictures enough to guarantee all-A's just slows most shooters down way too much for that to work. Holsters can be wherever you want them on your belt, so if you want an appendix-carry position, for instance, this will let you do it. This is the division for people who want to shoot iron sights and don't mind a bit of recoil but otherwise want go really fast - but you'll want to shoot .40.
Carry Optics: This is a relatively new division, but it is proving popular. It allows (actually requires) a slide-mounted red-dot sight. The base gun must be from the same approved list as for Production, and must remain DA/SA. This division also has a 45 ounce weight limit (including optic and empty magazine), which leads to some interesting weight-saving requirements on a lot of steel-framed guns. Magazines can be the same length as in Limited with no capacity limit. This only allows minor PF scoring, and with no fixed round count limits on the magazines, it's insane to shoot anything other than 9mm. Holsters have to be gun-bucket types (not the trigger-guard grabbing race holsters common in Limited and universal in Open), but they can go anywhere you want on the belt. This is the division for people who want to put a red-dot on their slide (and don't mind paying for the milling to get that done and to make weight), run extended mags, and shoot just as fast as the Limited guys. You have to shoot A's, but the red-dot and minor PF ammo makes that more easily achieved than in Limited or Production.
Open: This is the nearly-unlimited division for the race guns with compensators and frame-mounted optics and 171mm magazines. Everyone who shoots this loads their own ammo. This is the harder drug that some people get into after a few years with the other stuff. There are CZ and Tanfoglio options for this division, so I mention it as a possibility, but I wouldn't suggest it for an entry point unless someone is ready to throw $5k-6k at racing gear from day 1. I know a couple of people who have done that, but they're either very rich or very broke.
OK, those are the divisional flavors. Different guns will be suitable for different divisions, and the division rules make some guns (an iron-sighted SAO 9mm, for instance) non-optimal for anything. They're all fun, but if you're contemplating buying a gamer gun, it's best to start with some plan for shooting a particular division. You can always get different gear and change divisions later, but you want to buy something that fits in whatever you think is most likely to be fun.
How CZ and Tanfoglio relate
Now, we're almost ready to answer your question, but first lets straighten out something that people often get confused about. CZ and Tanfoglio guns are
similar, but they are not the same. Decades ago, Tanfoglio (an Italian firearms maker that's only a few centuries old) got contracted to build some CZ-pattern guns during a time when CZ was still somewhat communist and couldn't/didn't export in volume and to all western/democratic countries. Tanfoglio got the plans, tooled up, and started making CZ-pattern guns. But, before long, they started tinkering with the design, and began an evolutionary divergence. Meanwhile, the politics changed, CZ started exporting more broadly, and started making their own refinements to their designs. For the past ~20 years, CZ and Tanfoglio have competed in the same competitive shooting marketplace. They have each borrowed things from each other. At this point, neither is a clone of the other... and parts interchangeability is pretty minimal in most cases. But they do have
similar internal designs, and
similar ergonomics and levels of performance. Most people who are familiar with one maker's gun of a broad type will feel comfortable with a gun of the other maker. People who like one generally like the other.
One other point: EAA is the primary importer of Tanfoglios into the U.S. market. They don't make anything. In the last year, another importer - IFG (Italian Firearms Group) - has come online, and is allowed to import
only those Tanfo' models that EAA doesn't. IFG's stuff is currently even less widely distributed than the EAA competition stuff, but there are a couple of their options that I would rate as particularly relevant to the Carry Optics division. Otherwise, I probably wouldn't worry about them, and just focus on the EAA-imported models, because IFG stuff is both harder to find and introduces the whole large frame/small frame rabbit hole that
I am not going into I swear.
Finally, some concrete, responsive answer to your question
CZ and Tanfoglio have viable options in each of the divisions discussed above. Better than viable. Let's go through them.
Production: You're looking at 9mm DA/SA guns for this. 4 of the last 5 USPSA Production national titles have been won by a guy (Ben Stoeger, who also won with Berettas before then) shooting a Tanfoglio Stock 2.** That's a bull/cone barreled gun with a full-length dustcover and a chrome finish. It's a little bigger and heavier than a CZ Shadow, but, like all Tanfoglios, has a deeper undercut to the beavertail (shorter trigger reach) and trigger guard than the standard CZ's and Shadow. There's also the Stock III, which is black rather than chrome, just a touch longer, has a rail on the bottom, and has a straight (not cone/bull) barrel. I think Stoeger uses these for his international IPSC matches, dues to slight rule differences, so he obviously thinks they work just as well.
Before Stoeger made the Stock 2/II's (same thing) popular, CZ Shadows had become the dominant gun among people who wanted to shoot a steel-framed gun in production... and I suspect they are still the actual market leader. There's nothing that the Tanfo will be technically capable of doing that a Shadow cannot, but some people prefer the heft, beavertail undercut, and more aggressive checkering of the Tanfo. And that's why CZ came out with their Stock-2-killer Shadow 2, which basically adopts those features of the Stock 2. They're very nice guns. I honestly don't think you can go wrong picking between a Stock 2 versus a Shadow 2 - if those aren't the 2 best Production guns in the world (and they might be), then there is, at the very least, nothing that is better at all. If you show up to shoot Production with one of those, people will say, "Ah, a man of culture." Not really, but you won't ever have to answer questions about "why."
As between the two of them, pick the one that you like best in your hand. If you can't handle both of them, pick the one you can handle (assuming you like it). If you can't handle either, pick the one you like the looks of better. No, seriously, that would be a fine way to choose. Just remember all these guns have removable grip panels, and there are multiple options for each, so don't choose based solely on liking CZ's beautiful electric blue grip panels. Unless you want to.
Limited: This division is mostly filled with double-stack 2011's, most of them costing $2-$4k Tanfoglio and CZ offer awesome value in this space, with (IMO) no performance trade-off other than a marginal edge to 2011's in terms of how spectacular the trigger can be gotten. I think it's actually easier to keep the Tanfo's and CZ's reliable versus the 2011's, but you have more options for part sources and mods on the 2011's - not that there aren't a good variety of aftermarket things for
Tanfoglio's Limited model is basically tailor-made for this division. That's what I have shot for several years. It has been robust, every bit as reliable as the Glocks and other service-type guns, and has entirely satisfied me. It's way more accurate than I am. I truly, truly, truly don't think I would have performed any differently with a 2011 costing 2-3 times as much. I've made a bunch of mods to mine (as anyone shooting Limited does to their guns), which I'm happy to discuss if you have specific questions.
Similar to the production gun discussion above, there's a CZ (the Tac Sport, no longer in production) that was similar to the Limited, but with less undercut and less good checkering. It was based on a larger frame (similar to the CZ 97), and many people did have grip-reductions done on them to make them comfortable. And then CZ came out with the Tac Sport Orange, which, like the Shadow 2, adopted a lot of the things that maybe made the Tanfo' better (ergonomically for some people) than the prior CZ. So now this is another area in which I consider these to be very, very competitively equivalent guns. I recently bought another Tanfo' LTD, but that's because I know those guns and already have the spare parts. If someone took away my Limited gun and magazines and spares and replaced them with a Tac Sport Orange, I'd be mad because of the principle of the thing, but I'd get over it. Wouldn't change a thing about my shooting.
Once again - handle both if you can and buy the one you like better. No wrong choice.
Carry Optics: I have less to offer here, except to note that I think most of the DA/SA guns we're discussing are going to need slide-milling to make weight (even if it may just be the same milling for mounting the optic). The new IFG-imported Stock 1 (yes, it's got a lower number but is newer... freakin' Italians) looks like an interesting choice for this due to its slightly lighter weight IIUC. Similarly, I might look at the Shadow (not-2) for weight. But you should talk to someone who knows more than me about this.
Open You're not gonna do this right now. If you are, let me know, because I have
opinions on this topic, having just had an open gun built on a Tanfo' LTD base (which I love, BTW). But this is like picking a heroin/cocaine combo for your first foray into drugs (not that I think anyone should do drugs, just making an analogy). Probably not advisable.
Conclusion
I fully acknowledge that I didn't tell you to pick one brand over another. They're very comparable... it really is just taste and preference on little ergonomic things. If you just can't decide, go with the one(s) you can get a better deal on or can find in-stock when you're ready to plunk down your money.
* Power factor is an integral component of most of the practical shooting games. It is basically a momentum calculation. Different sports have different momentum figures. USPSA actually has
two different power factors: 125 for minor, 165 for major. For divisions that allow major scoring, A-zone hits (and steel) count 5 points, C-zone hits count 4 points, and D-zone hits count 2 points. For minor, A-zone hits (and steel) count 5 points, C-zone hits count 3 points, and D-zone hits count 1 points. Obviously, major PF generates more recoil, but the scoring advantage is pretty big. Minor PF really, really need to shoot a very high percentage of A's, whereas major PF shooters generally don't need to sweat C's at all. Some divisions score
everything minor, though. And some divisions that do recognize major require a different minimum diameter bullet versus the overall baseline requirement of at least a .355/9mm bullet. At major matches, your ammo will be chronographed out of your gun and bullets will be pulled and weighed. At local/club matches, it is almost invariably based on the honor system where you declare whether you are shooting minor or (in divisions and calibers where permitted) major.
** IIRC, the interruption in his streak was by a guy shooting a Tanfo' Lim Pro - a slightly lighter, though still quite robust, gun without the full-length dust cover or bull barrel. EAA stopped importing those right before that guy won a national championship with one, and then they became unfindable. This is one of the models that IFG is now planning to bring back into the states, though I don't know if they're actually here yet. Their lower weight might make them interesting as a Carry Optics base gun.