Having owned two of the guns referenced, and having shot all three fairly extensively, my observations are as follows:
XDM5.25: not a bad trigger for a striker fired gun. Good accuracy and decent sights. Decent ergonomics. M&P 5" Pro: Best ergonomics of the three, great trigger with the Apex system, great accuracy. Glock 34: (My Choice) Great accuracy, stock trigger can be tuned to be almost as good as the M&P. Mine is a fairly crisp 3# with minimal over travel. Not the best ergonomics, but anyone can learn to live with it. Although I don't condone it, many, myself included, shoot lead bullets through the stock Glock barrels. I've got roughly 22k rounds through the 34. All three of these pistols are about as reliable as a mechanical thing can be. The availability of after market and factory parts is also a factor in my decision. If I ever have to fight with a handgun, it'll be a Glock, so that's what I shoot in IDPA/USPSA. If that were not a factor, I'd be looking closely at the M&P line. Good luck making your decision!
Savage