well, check my sig for numerous discussions about this very thing. Go to compact talk I believe there is one up top going right now. If you don't feel like doing that, I'll go ahead and give my take on it.
2 more rounds
grip doesn't feel like a 2x4 with a dent for your thumb
made in america, not croatia
no special extended mags, just get full size mags and slam em in then shoot till it hurts (which will take a few thousand rounds in a session)
Mine has 900 rounds (8 different kinds of ammo) in a month with one malfunction on round #5 (I didn't field strip it before I shot it) just a little lube on the barrel, chamber and rear rails. Zero malfunctions since then.
you don't have to have any tools to field strip, the manual say use the tool but you don't have to.
it doesn't look like someone projectile crapped a glock (personal opinion)
lower bore axis (much lower) changes grip angle a little but recoil is milder because of it.
you can smooth out the trigger to IMO
way better than the XD in an hour at your dining room table (did mine this weekend)
i think the trigger is better from the factory anyway
you can get parts for it and fix it your self (or have your smith fix it) instead of sending it in
made in america, not croatia
the measurements on the net may say that the xd is smaller but when you put them side by side the M&P feels smaller than either the XDsc or baby glocks. The xd has all of those 90 degree angles and smith went out of their way to make every edge of the M&P comfortable. One handed reholstering is easier, it more ambidextrious supposedly (I'm right handed)
2 more rounds, and last but most importantly, it's a smith & wesson
get what you want but the M&P felt so much better in my hand. I went back and grabbed a XD the other day and it felt
horrible
did I mention that it's made in America?
here's a thread that is similar
http://mp-pistol.com/boards/viewtopic.php?t=3098