I used to have one of the old Ruger PC9's. It was very reliable and had a decent trigger but felt a little clunky, and eventually I sold it and went to AR-9's which I found to be more ergonomic. I haven't shot the new model Ruger carbine, but I've seen quite a few people using them and they seem to run well.
I still have a Colt AR-9 that takes Colt SMG magazines. Colt pattern AR-9's have worked well for me and I've shot a lot of short range 3 gun matches with them. More recently I've gone to a JP GMR-15 which uses Glock mags. JP makes very nice rifles and the new JP-5 with delayed roller bearing action would be top of the line for PCC's. However, it costs more than $3000 so it's expensive. I think the Glock magazines are a bit more reliable than the Colt mags and I'm happy to have switched to them.
PCC's are a lot of fun and relatively cheap to shoot.
