I have a 550 and am very satisfied with it. I wanted manual indexing after using another brand's auto indexing and not liking it. Granted, it was probably the somewhat finicky operating press rather than just auto indexing, but things don't move along until I'm happy.
Using powders that can't be double-charged eases my mind quite a bit, too, though with .45 ACP that's possible but would be noticeable if so charged. I have a light in the center and each case gets a visual inspection before a bullet is placed in it.
