There are a lot of pistols I enjoy. Some I like to look at more than shoot, some are just "cool" and fine for the occasional range visit, and others are what I take to training courses, practice with regularly, and would bet my life on.
For me the only pistol that falls into the last category is the M&P, but I would also put GLOCK in that category if I couldn't choose an M&P.
HKs, and Sigs are some of the coolest pistols, and I really like them, but I can't drive them as fast and I'm just as accurate with the M&P as those high dollar pistols. Don't get me wrong, there are a lot of great pistols out there, and if I had to carry a Sig in a duty or WROL scenario I'd be comfortable with it, but I would know that I would be at a bit of a disadvantage when compared to the M&P.
I would only change 3 things if I controlled S&W:
1. Lighten the duty trigger by maybe half a pound (I'm fine with the stock 2013 triggers...love em actually, but a lot of people would be more comfortable with a little lighter trigger)
2. Stipple the frame or change the texturing to make some traction in all conditions
3. Remove that stupid hole in the chamber and frame that can let sand and other debris into the action which could cause failures. I think this will be one of the primary things that keeps the M&P out of the hands of US military. it's useless in low light any way..