I use the Comp-Tac Gladiator. It is a Kydex outer shell mounted to a leather back. Works very well and has been almost impervious to wear. I will say the can't seems a little severe, for me anyway. I have several Comp-Tac holsters & mag pouches and the quality and service is each top notch.
All major manufacturers have something for the M&P. You need to decide on what material it is to be made of and what other features you either need or want...ie. retention strap, degree of cant, how much you want to invest, will this be for IDPA only or for daily CC as well. etc...
I have been using Kramer holsters both IWB and OWB for IDPA with my M&P Full Size .40 as well as a couple of DeSantis and a Milt Sparks VM-2 for the ultimate in carry comfort.
Hope this somehow helps you out. Some of my M&P's actually ride in a Glock 20-21 holster as they fit quite well. Might work for you as well.