I finally had a chance to shoot my M&P 2.0 9mm 4.25", and my Glock 19X yesterday. I shot American Eagle 115 gr FMJ, Federal 115 gr 9BP, Blazer Brass 115 gr, Blazer Brass 124 gr, Remington Golden Saber 124, Golden Saber 124+P, Speer Gold Dot 124+P, and Hornady Critical Defense(unknown grain).
Both guns shot everything perfectly, except the 19X stumbled on the truncated cone Critical Defense. I had two Fail to Feed malfunctions in the first 7 rounds, I stopped at that point and unloaded that magazine. I certainly don't blame the Glock for that, I have had quite a few pistols over the years not run truncated cone bullets reliably.
One thing that annoyed me, the Glock continually threw brass at my head, and twice I ended up with a hot casing down my collar. The M&P threw every fired casing perfectly up at a 45 degree angle and to the right. The Glock was throwing casings erratically, but mostly to the right.
Both guns felt great in my hand, both triggers felt the same, both drop empty mags freely. They are very similar, except the Glock cost $230 more. The Glock does have Tritium sights, and came with two 19 round, and one 17 round magazine. The M&P came with two 17 round mags, and standard sights.
My 2.0 is my first M&P, but not my first S&W autoloader. It certainly wont be my last. I'm considering a 2.0 in 40, just because I want another 2.0, and I don't have a pistol chambered in 40.
I expected my 2.0 to run reliably, and I wasn't disappointed. I ran 470 rounds through it, and it never missed a beat.