I carry a Glock G19 for my CCW and I have been looking at the M&P hard here as of late for my CCW gun. I really like it and is close in the way it breaks down as the GLOCK.
How do you like your M&P? I hear there are a few different models out what one did you pick?
The only thing that worries me on the M&P is the back strap after time will it break down or will it with stand the abuse.
I can only tell you how things were for me, but the M&P was the best trade off of ergonomics, size, felt recoil and capacity (which initially wasn't a factor as I was more concerned with size). The recoil, again, I don't know how they managed this, is surprisingly light and controllable even without the pinky extension. I ran 150 (flawless) rounds through it on the steel challenge course at USSA (which I had never been on before) and I felt far more comfortable in only that short time with the M&P than I have with any other gun I've carried. One of my main concerns was well placed follow up shots, which (for me) was a huge improvement over the KelTec - although a completely unfair comparison.
Also, S&W is running the two free mags rebate which was also a factor as it effectively dropped the price of the gun by $70-$80.
The back strap is attached via a metal rod that inserts just behind the mag well and runs through a holed protrusion on the inside of the grip. I don't see how the thing could wear out, but even if it did, I think extras would be only a phone call to S&W away.