For handgun and rifle up to 7.62/.308, the 550B is a great machine; I use mine for all my handgun loads, and rifle stuff in 223, 308, and 30-30. The problem with most rifle cartridges is you're still going to have to do most of the case prep stuff one at a time anyway (inspection, cleaning, lubing), so you don't really save much time by using a progressive on those (but carbide dies are a big help). Regardless of what press you end up using, you're still going to need a set of calipers so you can set your cartridge overall length, and a good scale so you can check and double-check your powder throws, bullet weights, etc. If all you're planning on loading is 45 ACP, you may as well get something like the Square Deal B, which is simple and easy to use, but isn't as easy to switch over to other calibres and uses special small-diameter dies only available from Dillon.
Regardless of which machine you end up using, reloading isn't something that you can do in the back of your mind while you're watching TV; you have to pay attention to each step, and you want a clean well-lit area to make SURE each one is done properly. The 550B requires you to spin the shell-plate to a new position each time you crank the handle, and that's when you want to take a good look and SEE the proper powder charge in the case before you set the bullet into the case.