Your needs should dictate the press you need. I started with a 550B about 11 years ago. I didn't mind that the press did not auto index at all. Thinking back I believe that press produced 300 to 400 rounds an hour.
The only reason I sold the 550 and moved on to the 650 was I didn't like the fact that it only had 4 stations meaning I couldn't use a powder check die.
One thing that I tell everyone buying a progressive press is get a powder check die, it's cheap insurance.
In all honesty the 650 is not much faster than the 550. Mine certainly has not produced the advertised rounds per hour.