D-A
To be honest with you I use the RCBS Pro-2000 the most but part of the reason for that is because of where it is positioned on my bench. I have found that all three presses are reliable, relatively simple to setup and use, and the ammo they produce is capable of shooting sub 1/2 inch in my rifles when I do my part. I have a lot of use on all three and have not had any major glitches except for one broken pot-metal part on the RCBS that was replaced in very short time. I believe I caused that breakage, has never occured since I replaced the part. The Dillon and Hornady use primer feed tubes, I prefer the strips that the RCBS uses. Once you get using a progressive you can produce a lot of ammo in short time, that is my goal since I have no interest anymore in fussing with my reloads.
Here are some opinions, which are only my personal experiences.
Dillon 550B - somewhat complicated to setup, found the instructions a bit vague but got the press working in a couple of hours. Does not take long to get a smooth operating procedure going. Great shooting ammo. Cast aluminum, excellent fit of parts, good backup, get the spare parts kit just in case.
Hornady LockNLoad - big solid press, easier to setup and get running. Have the auto case loader, very solid machine and excellent ammo. Fastest of the presses I use. Auto indexing is very handy, the other two presses have to be advanced by hand. Last press I got so it went together best because I had some experience with the others. Hornady asked me to help with a re-write of their setup manual - I am a good person to do that since I scew-up most everything I touch. Made some points that they would have over-looked, they never realized anyone could be so dumb...
RCBS Pro-2000 - very robust, cast-iron beautifully built press. Simple to learn to operate, setup was somewhat complicated for me but I have problems following instruction manuals - first progressive so it was intimidating. In reality it is a simple press to maintain - I can totally dismantle it for cleaning, very good ammo production, use primer strips and very reliable, excellent accuracy. Prefer the direct operation of the measure also, the case operates the powder thrower, no other linkage.
Got a 650 Dillon but have not got it going like the other presses yet - too busy shooting the ammo I make on the red, green and blue presses.
I admit to initially wondering if the ammo would shoot accurately - no sweat plus you can produce hundreds of rounds per hour. Just make sure you have lots of components - amazing how fast the powder measures empty!
Good luck on your decision - perhaps the best advice I can offer is to shop around and find the best deal - they are all good machines. If I had any major problems I would tell you, nothing like that has happened. Have loaded many thousands of rounds with no headaches - just lube occasionally, keep clean and covered between between uses. Die setting is easy, I find the Dillon is not quite as ergonomic for setting the bullet on the case mouth, personal preference I guess.
