I've had one for 3 years. It feels great in my hand. It has the same kind of sights and trigger as a real self-defense combat pistol. It fits several of my favorite holsters. The price was right. I can get an adapter to fit it with a silencer-- and I did. That alone made the purchase of the pistol worthwhile.
But it was NEVER very accurate. I'd shoot a High Standard with open sights and get a 2" group, all in the black. Then I'd shoot a S&W model 34 revolver and get a 4" group, with half in the black. Then I'd shoot this Walther P22 and get a 6" group, just a few in the black by luck.
The gun was reliable when it was new, and clean. Then as it got older, it required more and more frequent cleaning. Admittedly, the suppressor helped get it dirty faster. But eventually, even cleaning it didn't make it reliable. It had to go back to S&W for warranty repairs. Now that it's back it's 95% - 99% reliable when clean, which is good enough for me. But shipping it to S&W cost $45.
When I bought this thing, I was unfamiar with the Sig "Mosquito." Now I think I should have gotten one of those instead.