Lots of folks love 'em and swear by 'em; lots of folks don't and swear at 'em. The P22, truth be told, is a toy on steroids. It's also not a Walther product but rather one made by Umarex, which is Walther's parent company; Umarex makes air guns, which ought to tell you all you need to know about the P22.
Seems to me that the forum has had dozens of threads on the P22, including several in the past few months alone.