I used a few of them on my M&P9c.
Liked them well enough.
The only issues: They didn't fit tight enough to the bottom of the mag to keep the thing from sliding as the mag was mounted in a belt holder. This can absolutely hinder reloading...as you now have to work against sliding the XGrip + normal reloading tension.
The way MY hand fit on MY gun - I'd get pinched where the XGrip met the bottom of the gun grip.
-J-