First progressive I bought was a Lee Pro-1000. Most of the decision was based on the attractive price/"features" ratio. Wish I'd spent the extra money for a Dillon. I've loaded tens of thousands of rounds on my Pro-1000 press. There's a small learning curve to running one- if you are one of those people that wants to open a box and start making ammo with no adjustments, the Pro-1000 is probably not for you. But once you figure it out, it's so easy my 6-year-old daughter can run it.
I make this comparison all the time- a Lee Pro-1000 press is like a Craftsman lawn mower. The Dillon is like a John Deere. Most people don't need a commercial-grade machine to mow their lawn. Some buy the Deere anyway, and that's great if you have the money and want commercial-grade stuff. If I needed 10,000 rounds a month for competition, you betcha there'd be a Dillon 650XL with case feeder bolted to my bench. Since I shoot 10% of that on a good month, my Lee Pro-1K works just fine. Lee's niche is providing features not normally found on inexpensive models at a great price. The Dillon 550 doesn't get you a case feeder or an automatic index. The Pro-1000 does.
The Lee primer feed system is the biggest PITA. Unless the entire feedpath's kept scrupulously clean reliability is awfull. The slightest bit of dust or residue build-up in there and you'll start getting empty pockets. It's extremely tough to spot impending trouble before you get one, and the path itself is long and difficult to clean thoroughly without some disassembly.
"Slightest bit of dust?" "Scrupulously clean?" Please... this is not true.
The system is gravity-fed; as long as you keep primers in the chute, they keep feeding. The feed chute is about what, 4" long? And open on top? A small paint brush wipes it clean in seconds. Just keep it dry, no lube required. You can spot trouble because it's open and you can see if primers aren't feeding. It's really simple- as soon as the primer feed tray is empty of primer- you can see the stack in the chute below the tray- add another 100 primers. Then they feed quite well.
I've also grown less-than-comfortable with having a hundred or so semi-loose primers rattling around in a plastic tray pointed in the general direction of my "ruggedly handsome" face. If I'd known about the warning/disclaimer in the manual that the use of any other brand of primers except Winchester and CCI due to the "increased possibility" of mass detonation, I'd wouldn't have bought it.
I've heard of Federal primers going off in handheld priming tools. Lee doesn't like the Federal primers because they are more sensitive. At least he's honest about it.
It also requires a great deal of practice and care to avoid getting a lot of "high" primers. Seating is on the "down" stroke and the "feel" feedback is vague at best.
I will agree with this- but once you get used to the press (and know how it works) this isn't a problem. Usually I find this is caused by people trying to go too fast and not bottoming out the ram fully before changing direction.
It's also not, IMO, a good choice for frequent caliber changers. Change-over takes longer and involves more readjustments to get back into full production.
What??! It takes me about 2 minutes to changeover calibers in my Pro-1000 & that includes changing discs in my Auto-Disc powder measure. I have all my dies preloaded and preadjusted on turret plates. I have extra shellplate carriers already setup for the caliber to be loaded including the case feeder parts. And the cost to have a spare shellplate carrier ready to go is still less than buying a spare Dillon toolhead and shellplate. Otherwise, if I have to change a shellplate over from scratch, it might take a couple more minutes- call it 5 minutes total to change from 9mm to .45 ACP if I didn't have spare carriers.
I've been a lot happier with my Dillons. I'll trade auto-indexing for easier set-up, easier routine maintenance, fewer chronic problems and more consistent quality in my reloads any day - even at the difference in price.
Again, we're talking the difference between Craftsman and John Deere here. I'm happy with the Pro1K & my consumer-grade lawn mowers. But then, I know how to work on them. Some people do not. I'm not bashing the Dillon- they make a darn good machine- but not everyone needs one. As far as "Consistent quality" goes- ammo loaded in my Pro1K seems to shoot as well as the ammo loaded in any other press people talk about owning. OAL seems to hold true. Powder weight seems to hold very close (-.1/+0)