RCBS makes decent stuff (most of my dies are RCBS), but my Dillon RL550B is great, and the Dillon dies are awesome. The only thing I'd say about the 550 is it's manual advance. Had I realized that before I brought it home, I MAY have opted for the 650, but even with manual advance, I can still crank out ammo way faster than I coul single station. The Dillon dies I love the most are my .357Sig dies. I've been reloading .357Sig with a single stage and Lee
barf
dies. The effort required to resize the brass was insane. Wasn't much better with some Hornady Custom dies that supposedly had some kind of carbide-like ring. The Dillon dies cost twice as much as their normal straight walled dies, but well worth it IMO. With the exact same amount and type of lube on the cases, the dillon dies require virtually no more effort to resize the .357Sig brass than to resize 9mm or .40. And I don't think you can beat the "Lifetime No-BS" warranty.
i load precision rifle rounds and pistol rounds. but only use a lyman automated powder measurer. do you still get the powder accuracy with one of those progressive presses?
My $.02... For precision rifle reloading, don't go progressive. Stick with what you are doing. I use my Dillon for handgun only at this point, although I would set it up for rifle if I needed a lot of ammo that didn't need to be tack-driving accurate (Like SHTF M193 Spec). My hunting loads will always be loaded single stage, with each load individually weighed. A little more or less powder will likely make much less difference in a handgun with a ~3" barrel than it would a precision rifle.