Mugsie,
I am very pleased with the Dillon. I load three pistol calibers on it currently, and keep two spare toolheads setup so I can rapidly change from .45ACP to .44MAG to .357MAG. Some folks make a big deal out switching the primer system I find it takes me a couple of minutes. (After a fair amount of practice!)
When I transition to loading rifle it'll be another learning experience. Case lube, deburring, case trimmers, etc, etc. I'll probably use the press like a single stage for rifle rounds to guarantee thoroughness.
I can crank out somewhere between 300 - 400 pistol rounds an hour on the 550 when I hit my stride. This did require some tweaks to my Dillon setup though. I highly recommend the following mods:
Strong Mount - gets the Dillon up off the bench and allows for mounting of accessory trays, brackets, etc.
Roller Handle - eased operation for me over the standard ball unit
Bullet Tray - puts the bullets close at hand
Empty Case Bin - by getting another bracket you can mount a empty case bin in front of the finished cartridge bin. Again, easy access to components
Spare Primer Tubes - I load up 3-5 primer tubes before I start loading so I can quickly reload the primer system
I usually buy from Brian Enos's site:
550 Accessories
If you scroll to the bottom of this page you'll see a 550 on the strong mount, with roller handle, bullet tray, and empty case tray. This is pretty much my setup.