I have an RCBS that uses the primer flipper as a feed magazine. It uses standard shellholders and works very well. It is comfortable to use. As Fred said, it has several small parts that are a bit of a PITA to deal with since you have to remove them to put the shellholder on and off. I only use it or 30-06 and just got an extra shellholder which I just leave on there.
I have my father's RCBS with the unviersal shellholder jaws. I haven't tried it because his model uses the plastic strips, which I couldn't find and am not interested in dealing with. I haven't used it without the strips because the primers are hard/impossible to put in one at a time.
Overall, I like to use the press mounted seater on my RCBS single stage. It's one at a time, but I just prime on the downstroke after depriming/sizing on the way up. This way I handle the brass one less time, which is more convenient. This is for low-volume stuff like 32ACP.
RCBS does make quality stuff that works well. I broke my original RCBS primer whan it was dropped on a concrete floor. I called RCBS and they mailed me a new one for free.
Drugs are bad because if you do drugs you're a hippie and hippies suck.
"If you kill enough of them, they stop fighting."-General Curtis E. LeMay