I haven't shot an M&P 9mm, but I can compare and M&P40 and XD in 40. (I have also shot the XD tactical in 9mm and most of the issues apply)
-For me, as far as grip angle it's a push, both are good.
-The trigger on the XD out of the box is mushy but smooth. I don't like the feel of it so much, but it is usually better than an out of the box M&P trigger.
-bore axis M&P kicks the XD's but. Which affects speed of follow up shots.
-balance. The tactical is a little nose heavy, but the design of the longer slide puts a fairly heavy chunk of metal out front, up high, and it MOVES. It made the gun feel very flippy and snappy to me compared to the M&P or a 4" XD.
-The M&P magazines seem to be a better design to me at least as far as quick reloads go. In the XD's favor, the magazines are stainless.
-sights.. from the factory i like the M&Ps a bit more, but honestly would replace both in a heartbeat. So far i am liking the look of the M&P aftermarket choices a bit more than the XD's. The XD choices seem to be very tall on top of an already tall gun. The extra sight radius on the tactical is nice, but doesn't buy you that much IMO.