I have a couple of ProMag Beretta 92 mags and they look ok, and generally they work ok too, but every so often, they seem to have a problem where the follower doesn't push up the round quite firmly enough to clear the front of the mag, causing a hangup. I took the mags apart and cleaned up the follower (kind of rough), but every so often, it will hang up. You have to take the mag out and slap it.
I have about a dozen mags for my 92 and Kel-Tec SUB 2000, and they all work 100%, even the rough looking parkerized ones, but I can't seem to get the ProMag ones to work all the time in the 92. I haven't shot the SUB 2000 yet, but I bet it's the same way.