I have and love both, but I prefer the M&P. The grip/feel is 110% better than the Glock's.
Triggers ... well ... I'd get a M&P Pro if you want to start with a decent/comparable trigger. Otherwise, be prepared to fire a TON to get the non-Pro to feel smooth (or swap to APEX kits, which I refuse to do for defensive guns). The one thing I really can't stand about the trigger is not the grittiness though, it's the d*mn rounded shape at the bottom. At the very bottom of all M&P triggers it makes a slight curve that I find incredibly annoying. My only resolution has been to keep firing enough so that I develop a callus on my finger where it rubs. The Glock trigger, IMHO, is nicer to start with, but over time I've come to like the M&P's.
M&Ps come with better sights (especially Pro) too, I think. My Glock is a Gen 3 and it has the plastic sights (I don't recall if Glock changed these on Gen 4s?). Someday I might change them.
As far as accuracy/reliability, they're identical. I shoot them both equally as well. I've had one stove pipe in the Glock, which is really nothing over the 1000s of rounds through it (but I made sure to take some pics to refute its "legendary reliability". As far as I can remember, and I'm not saying this just because this is a M&P forum, I have not had one in any of my M&Ps.
Holsters and gear are equally abundant. For a while, M&P magazines were impossible to get, but I'm not sure this is still a problem since I have stocked up over the years.
What else ... ?