If you've got the real estate to keep the 550, I'd do it. I don't. I thought seriously about a 650 when I bought my 550 in 2011. I was afraid of the progressive aspect, so I did the 550. 4 years later, I added a case feeder to the 550. It's an add on that is twitchy at best. I got a great deal on a 650 with case feeder and was really happy with it. Then I started shooting revolver and needed deep primer insertion. The "push" seating with the 650 never got me what I wanted. I've since replaced it with a used 1050 which seats on the down stroke. Because of space constraints, the 550 and 650 have been sold for at least 80% of Dillon new. The 650 caliber changes are simple compared to the 1050. I'd had have stuck with the 650, if not for the primer seating. It's a great press. Had I the space, I'd have a 650 and the 1050.