I looked at all thee of the $500ish polymer pistols that are frequently pitted against each other, the glock, Springfield XD, and the M&P. it is important to fire the pistols before purchasing to ensure a good fit. I was sold on the Glocks simplicity and reliability and then I handled one and could not get a good fit in my hand. The XD was much better, but the M&P fit like a glove. The angle of the grip, it's size (adjustable, I found the medium strap to work the best for me), and it's texture all seemed great and it pointed more naturally to where I wanted to shoot than the glock.
You can't go wrong with ANY of the above three stated pistols, as long as you know what fits you, the shooter.