I have a Dillon "Square Deal B" for pistol reloading and a "650" for everything else. Over the years I've had to replace parts and Dillon difinitely has a "no BS" policy. Great people to work with.
As far as the 550, I've never used one but have a brother-in-law that swears by his. If I had it to do over again I would probably buy a 550. The "650" is more press than I need. Maybe you would like to take the "650" off my hands, heh Skinny??
muledeer