I had a P22 for a while. It was a fun little gun, and I bought it for the same reasons you are considering it. It has the shape and ergos of a larger auto, and I wanted to use it for cheap training. I never had any malfunction issues with it. It did disagree with some really old Aguila, but I blame that on the ammo, not the gun. It ate everything else just fine, from high velocity CCI's to cheap Federal and Remington ammo.
As others have noted, the accuracy is not great and it's probably not going to be a gun you're going to be handing down to your kids. I ended up selling mine because I had a friend who liked it more than I did, and I gave him a good price on it.
I have experience with one Sig Mosquito, and that pistol had a lot of feed problems. I know n=1 isn't a very good sample, but it didn't instill much confidence in the design for me.