"How does it stack up?" is a very open question. I don't get as good a groups with my P22 as I do with my MKIII Hunter, MKIII 22/45, 22A or Single Six. Haven't had the P22 that long, so I may get better with it. I haven't been able to shoot the P22 with nearly the accuracy I can the others. So I guess I can say, for now, it is not as accurate. However, I wouldn't expect to be as "accurate" with a 3.4" barrel as I would with pistols that are heavier and have 5.5" to 6 7/8" barrels and adjustable sights.
Other than occasionally having a first round feed problem, I've had no problems with the P22 mechanically.
The P22 is lighter, more compact than the others. It has advantages for carrying and storage. It stacks up pretty well in the fun-plinker category.