Tried one when I was in the States in June.
They seem OK, the guy in the shop said it was almost impossible to chop a ball, as the feed system has some kind of gate installed which stops a ball feeding incorrectly when the trigger is pulled, in saying that I managed to burst a few when I upped my rate of fire.
I'd say they are on a par with a stock impy, good gun but there are a lot better ones out there, but obviously a lot more expensive.
I put about half a box of paint through one, the trigger is a bit clunky (clunky?????). I was told its adjustable, but no one in the shop knew how to do it, burst about ten balls mostly in the breech so not overly convinced about the new feed system and I also found the trigger a little long.........other than that seemed OK
Hope this helps