I recently went through the same thing you are right now....
I went to the local gun shop and just decided that I would buy the one that felt the best in my hand... because i figured all of the choices are going to be reliable, as they are from major companies.
Of all of the ones you mentioned, the M&P Compact was the one for me. It felt like it was designed for my hand. The controls are easily reached by my thumb, I really liked the trigger, and with three interchangeable grip pads, you can tinker with it until you find the one that fits your hand. It just so happened that the one that was on the gun at the time was perfect for me....
The XD felt a little top heavy to me, and the Glock 26's grip was too short, because i have rather big hands.
I am currently saving up for the M&P Compact and I can't wait to get to the range with it!!!
Good luck in your search... you really can't go wrong with any of those mentioned arms, so take a saturday and head to the gun shop and handle as many guns as you can.... it will be like a little mini vacation to paradise!!!
D-Bak