I can't say enough good things about my P22. The did have issues in the past...however I don't believe that is the case anymore. Walther has fixed all the problems, and any new guns will run flawlessly. To be sure, make sure teh serial starts with an "L", and the magazine should have an "A" or "B" on it.
The only downfall to the P22 is it's hunger for expensive ammo. CCI mini mags work great for me. However, it seems that lately it's been doing OK with the cheap stuff. I buy the Federal high velocity hollow points now for $18/525. Not a bad deal, and the spring seems to have lightened up enough to limit any cycling problems I had when it was new. Also, magazines are hard to come buy, and are pretty expensive.
I don't think you can go wrong with it. I also prefer the 3.4" barrel. I don't think the extra 1" longer front sight you get with the longer barrel is beneficial.