I have five 450 presses. The first one worked so well I started looking for them at gun shows and garage sales and bought whenever I found good deals. I finally bought a 550 when they came out, tried it and really didn't like the primer feed, sold it and went back to 450s. I have one set up for 9mm, .45, .380, .30-06, and .308. I don't change calibers, I change presses and leave them set up and adjusted for the loads I use.
I had a lot of trouble with the primer feeds on all of the presses so I decided to use an RCBS bench mounted autoprime, and then put the primed brass into the 450. A bit of extra work but it produces great ammo.
Do whatever works for you, but I do definitely recommend the autoeject feature. It's great.