I have an RL450 bought new and still running. I can't begin to count how many rounds in various calibers it's loaded; several thousand this year alone. I consider it the best reloader ever made by anyone at any price. you can have your 550 if you want; I'll stick with my manual operation. No double charges, no empty rounds, nada. When I get enough money saved up, I'm going to buy another used one for dedicated 223 and 380 loading. I've had a 650, SDB, and a 550. I sold them all and still load on the 450. I may not break the world record for amount loaded in an hour, but I'm retired and don't have anything but time. YMMV. CB.
If you want your children to follow in your footsteps, be careful where you walk.
Beware the man that only owns one gun; he probably knows how to use it.
I just hope my ship comes in before my dock rots.