I don't like that much recoil, so I'd probably go with the 6CM. But, I have been a reloader for many decades so 'accurate' ammo just takes a bit of load workup.

Before you pick reloading equipment how much reloading will you do? If it is just for informal rifle shooting on steel or target then a good single stage press will work fine. Brand really doesn't matter. Whichever one you get I'd recommend a press with quick change die bushings.

Next step up is a turret or progressive. The Lee turret presses are good in their 'manual' form. I'd stick with the plain version. For shooting a lot then a Dillon would be better. Only your bank account limits which one you pick :) The 550 is a nice piece of kit.