I'm partial to the Dillon 650 myself, but I could see someone going for the RL550B if they weren't going to shoot as much. The two reasons I don't get a 1050 are #1 - It's considered a commercial machine, so the free replacement parts I get with the 650 isn't there, and #2 - Although it jams up much less frequently than the 650, when the 650 jams up (which isn't often), I can fix it 99% of the time by tapping it. When a 1050 jams up, it's much more involved.

Every year at the USPSA National Championships, the competitors fill out an equipment survey that is very comprehensive. USPSA is pretty much the gold standard for high-volume shooters, in case you didn't know, and at the 2015 Nationals, 93% of Limited Division shooters and 97% of Open Division shooters used Dillon reloading equipment for their match ammo. I have a link around here somewhere that showed the automatic powder dispenser on the 650 was the most consistent powder dispenser out there on any progressive press. It costs, but worth every penny and then some.

I sort of understand Mapper's polygamy, I do...