I have both and while I love both, the M&P 22 is more user friendly IMHO.
The Ruger shoots slightly small groups than the Smith, but not enough to matter to me.
I have had some ammo issues with my Smith, but I think it was just that, ammo. The Ruger had the same issues with the same ammo as well.
Personally, I like the M&P a little better than the 10/22 for shooting. I is accurate enough for me.
PS- my M&P 22 Compact will run the same ammo and not miss a beat.