My Walther P22 was finicky on ammo at first, but after a few hundred rounds, it's not fussy at all, runs like a champ. When I first got it, the front sight popped out and I had to replace it with one of the extras in the box, but it's stayed put ever since.
A friend has a SR22, and it was worse than the Walther for finicky, but a few hundred rounds of CCI Mini Mags loosened it up good.
A guy I worked with has the S&W M&P 22 compact. When he got it, a spring on the rear sight was missing.
Took him a couple tries to get the right thing from S&W, but he did get the right one, and we finally got to sight it in.
The S&W shot everything he had with him with no issues.
If I was buying a new one, I'd get the S&W, if for no other reason than I like how it looks.