I use both. I have two Rockchuckers I use to size rifle cases and load small volume stuff, and precision target loads.

I also have five Dillon presses, four are 450 models dedicated to single calibers that I shoot a lot of, such as .30-06, 5.56mm, .308, and .38 Special. I got tired of changing the calibers all the time and already had 2 of the 450's, found 2 more cheap and stayed with them. I also have a 550 that I use for .45, 9mm, and .380.

I can turn out a lot of ammo with the Dillons, even the 450.