Last summer, I bought a used one in .40 S&W. I mounted a Burris Fast Fire III on it, and went to town. Fantastic accuracy, and the recoil, even on the .40 was not bad at all.
A few weeks later, I happened to read about converting the M&P 40's to 9mm with a Storm Lake conversion barrel. I ordered one for it, along with a couple of 9mm mags, and now I have twice the fun.
I also have a M&P 40 Compact, and ordered a Storm Lake conversion for it. It took the recoil down a notch, and it's actually fun to shoot at the range now.
The barrels are available on eBay, or from several different places like Midway U.S.A., etc.
The conversions are literal drop-ins with no fitting needed. The feed ramp on the conversions is the same size as the .40 S&W, and there's not enough "slop" to cause any feed problems. Both barrels have over 1K rounds now, with no failures of any kind.
Congratulations! Any more fun, and the vice squad would be visiting you!
