While I am a big fan of S&W, and own several of them, I carry a Glock 23C. Partially because it is a fine weapon and partially because the agency I work for mandates it (although there are ways around it). I am very found of the 23C (and G19) and much prefer it to Glock's full size offerings. The compensation tames the muzzle flip very well without any of the negative side effects that the internet commandos claim will occur. Mine has proven itself on paper, at the range, during tactical training and just out plinking. The ergonomics of the G23C leave something to be desired, but the upside more than makes up for it.
That being said, the M&P truly seems to be an excellent platform. S&W took the good from Gaston's design (no I am not saying the stole or copied anything), added some improved features and left all of the bad in Austria. The only M&P I have ever owned/shot was the full size M&P 45. It was a very capable gun and a great shooter, I just did not need another .45acp sitting in the safe. I have recently begun contemplating picking up a M&P 9C.
I truly believe that whichever way you go, you will end up with a very good handgun.