I would personally go with the SR22, but I'm honestly more of a Ruger fan. Don't take what I say as gospel because I have no first hand experience with the Walther, but I believe I have heard that they can be a little picky with ammo, whereas from my experience and from other things I've read about the Ruger, it tends to eat anything. Plus if you ever have anything go wrong, Ruger will make it right.
The Walther P22 is awesome, but I would have gotten the Ruger SR22 it they had been making year and half ago. They say the Ruger breaks down easier also.
Anybody have trouble with the ambi mag release on the SR22? I handled one at Bradis last week and couldn't get the mag to stay in. Had to push mag release button in on opposite side to re-center it so the mag would stay in. As popular as they are, I'm guessing it was just a fluke.
I ordered a sr22 this weekend. Was informed it could be a long wait. Seems Ruger is way behind on sr22's & 1911's. My quote was $ 312. plus tax and s/h.
I have not shot a Walther or the Sr22, but I have Ruger MKII that I have owned about almost 30 years. I can't even tell you how many of thousands of round I put through this gun. It has been flawless! My favorite gun to shoot!