Based on my personal expierience with these two fine weapons (I'm leaving the Beretta out as I don't much care for it) I would say go with the CZ.
The ergonomics on both are very good if not the best in the steel pistol world. For me, its a toss up. Both guns fit my hand very well and I can't say one is better than the other. The Hi-Power is thinner from the factory, and has a shorter trigger reach. This doesn't matter to me as I can get a good grip on either and reach the trigger on the CZ with ease.
The operating principle of the two weapons is a wash. Since Hi-Powers are available in DA, I can't decide. My CZ did seem to give itself a trigger job after I had about 700 rounds through it. The trigger did smooth up although a gunsmith could slick it up even more. Doesn't matter as I ain't picky.
Accuracy is fine with either although I can manage tighter groups with the Hi-Power. The HP does sport a smaller magazine capacity which IS a problem in my book. The CZ really wins here. Oh, all (at least the majority) of CZ's new mags are made by Mec-Gar. Quality is just fine. Standard capacity magazines are more widely available for the HP, but quality can be spotty. Only buy from a reputable company if you plan to carry. One thing some have mentioned is that some CZ's exhibit problems feeding and chambering JHP ammo. Hollow point ammo is effectively illegal in the Czech Republic, so CZ, consequently, doesn't worry about it as much. Mine has fed everything I've loaded in, so no complaints there. CZ-USA is usually very willing to help, although some folks have had complaints. A good gunsmith can fix the JHP issue *IF* it pops up.
The price is better on a CZ75B (thats my model) and I got a great deal on mine. The only complaints I have are the crappy plastic factory grips. They just feel cheap. The grips from the P-01 would have been better. I've already replaced them with aftermarket pieces...wood ones from a local craftsman.
The other complaints I had were the mag brake (I straightened mine) and the fact that the mag well was too narrow at the base. The magazines were binding and not sliding out. I had to take a file to my brand new gun to make the mags fit and slip in and out. The pistol fired every time, but I didn't like having the remove metal from a new pistol. Oh well, the great prices have to come from somewhere and hand fitting and polishing is usually what gets sacrificed first.
Get the CZ, you'll be very happy. Oh, the money you save on the CZ is a good start towards saving for a nice FN marked Hi-Power.
http://www.impactguns.com has them right now. FN markings (not Browning) always garner more questions and stares...and I like the attention. My FN Forty-Nine always gets me noticed.