I actually got this PMR from a buddy that bought it when they first came out. He was on several wait lists and one of the newest gens came available so I got his older one. The difference between the gen I got and the one he got is mine has a fluted brl which Kel Tec has done away with for manufacturing speed reasons, my mags are not drop free when empty, and my frame is a bit less tacky to the feel. I put some rds through this pistol when it was my friends but not since I have acquired it.
As to the mag over the .22lr in a pistol, there is ammo that is formulated for the mag in pistol length brls that push more FPS. I like the advantage of 30 rounds too. If the rumor of a PMR-30 in .22lr materializes I will get one of them too. As a side note from shooting objects with a revolver in .22lr and .22mag the mag does a lot more damage. My brother had a SAA in .22lr/mag combo and the mag punched through things a lot better--unscientific but that is how the guys did their test in the old days (ask pigs and horses).