My personal opinion is that the M&P is a better choice if you are looking for a trainer. My M&P has a feel much like my XDM 9mm. A few ounces lighter but with similar balance and grip size.

I recently handled a P22 and feel that it is too light for my use. The SR22 is a little heavier though.

By the way, I have just shy of 2000 rds through my M&P with zero issues. I do have the impression that the bluing is not up to the standard of my XDM but that is just a feeling, I don't have any wear marks on the M&P.