I had been using a RCBS Rock Chucker single stage press. Since I shoot autoloaders, a single stage just didn't seem time effective. Since I did hand-priming, and since I practice tripple-taps, I could shoot them about two or three times as fast as I could load them. At Christmas I bought a Dillon 550 progressive press, and I have been thrilled with the result. The 550 is a four-stage press. Stage one is the sizing/decaping die, and the Dillon primes the case at the top of the upstroke. While I don't get exactly the same feel as I did when I primed by hand, since the priming occurs at the top of the stroke, I have developed a "feel" for the primer, and can I can tell if the case doesn't get primed properly. Stage two is and expander-die/powder measure in one die, stage three is the bullet seating die, and I have a Lee Factory Crimp die at stage four. With each pull I am preparing four cases at the same time.
The 550 has an optional case feeder which I didn't buy. I you decided to load additional calibers later on, changing the 550 is quick and easy. I have purchased a separate toolhead and powder measure for each caliber I load. I purchased a caliber conversion kit and a quick change assembly (which includes the powder measure) for about $150 for each additional caliber, and I can go from .45 cal to 9mm in about 10 minutes. Once the setup is complete, I can comfortably load about 250+ rounds per hour- faster than I can shoot them, and I have only been using the press for about a month. If I tried, I could probably load even faster, but I am willing to sacrifice some speed for safety and accuracy. If I had another couple hundred dollars, I suppose I could add the shell feeder, but I am satisfied with what I have right now.
Once piece of advice- if you go with a progressive, try to purchase the set-up video. I paid $20 for the Dillon RL 550 B setup video, and it was worth much more. I thought that setting up a progressive reloader would be complicated, but I watched the video once, then played it as I was setting up the press, and I had no problems at all.
I am glad I went with the progressive over the turret press. With the turret you are still only working on one case per pull, while with the four-stage progressive you are prepping four with each pull, and each pull completes another round. I still occasionally grin when I hear the "clink" of another round hitting the tray.
-Rick