Some years back, I loaded a comparison test of .220 Swift ammunition, with 100 rounds loaded on a single-stage Rockchucker, and another 100 rounds loaded on my Dillon 550, both runs using the same powder charge, primer, bullet etc.
The Rockchucker ammo had the once-fired brass trimmed and chamfered, primer pockets uniformed and cleaned, every charge individually hand-weighed to a tenth of a grain, etc. etc. The cases were primed on a Lachmiller bench-mounted priming press.
The brass for the 550 run was also once-fired, and was processed through my tumbler to get clean. That was ALL I did to prepare the brass....NO pocket-cleaning, NO trimming, and the ammo was loaded progressively, including powder charging and priming.
On a nice day. I took my accurate .220 HB varminter and the 200 rounds to the range. I fired targets alternately from each batch of ammo, so that any variation in conditions wouild not have a lot of effect on the end results. After a loooong day at the benchrest, the targets were compared. The average group size for each batch of ammunition was virtually identical.
As a direct result of this comparison, I now load most of my large-quantity rifle ammo on the 550, mostly the varmint calibers (.223 and .220) and the military calibers I like to shoot....7.62 NATO and .30-06. My handgun ammo is almost entirely loaded on the 550, too. NO cleaning of pockets, NO weighing of charges, but every round is checked with a case gauge after completion. These gauges will indicate when a case is in need of trimming, as well as many other conditions, and when any of the brass in a batch approaches maximum length, all of it goes to the trimmer.
I have three presses bolted to my bench, with a 40-year-old Lyman All-American turret between the two presses already mentioned. The Rockchucker gets VERY LITTLE use for actual loading, although it serves well for a lot of miscellaneous jobs. The turret gets used extensively for smaller quantities of ammo, and for many cast-bullet research projects.
After long and intimate experience with these machines, I'd hate to lose any one of them, but if I could have just one, it would be the turret press and no doubt about it. I agree completely with those saying that the single-station press is too slow and too restrictive. When I added the turret press to my bench all those years ago, it felt like I'd gone to Heaven, after using a Spartan C-press for some time! Note that I use the turret as a semi-progressive, processing each case from empty to loaded without removing it from the machine until complete. The RCBS powder measure is mounted in a die station in the turret.
My experience with Lee presses is limited, but I've been less than impressed with any that I've tried. My moulds include quite a number of Lees, but none of their actual loading equipment has ever reached my house. I agree with those who say, "Buy quality!" and have yet to regret the good stuff I chose (like that Lyman turret....forty years of HARD use, loading thousands of rounds per year, and still as good as new).
One old-timer's two cents....