I have had both the Xd9 and M&P9. I definitely preferred and kept the Xd9. It is about as ambidestrous as you'll need. Slide stop/release is the only thing non ambi but its a very minor inconvenience as you can just slingshot the slide when chambering.
The M&P 9s trigger pull just wasn't doing it for me but it does have an ambi slide release.
The M&P 9s trigger pull just wasn't doing it for me but it does have an ambi slide release.