I have both the auto prime and new xr hand held. the new one has some quirks that I'm not sure I like as well as some obvious improvements.
First it doesn't seem to feed so well and that may be because of its newness or it could be because the device that separates the primer being seated from the tray of primers. I'm guessing a little of both, it is a more complex system. Sometimes 2 primers will end up in the seating area and it is more difficult to straighten out than with the original. The trays are excellent and easy to load from a standard primer box. The lever stroke is a little shorter than the old autoprime, nice. The seating action has a nice feel, gentle but you feel the primer seat. It comes from Lee with a steel connecting arm. I'll give it some time to loosen up and some time to become more familiar with it before I decide good or bad. So far I have primed a couple hundred .38's and some .356's.