I have had 2, both in 40 caliber.
The first one, would not fire every time the trigger was pulled. If you cocked it and pulled the trigger, it would not fire until you pulled the trigger 3 or 4 times. I sent it to S&W and they "fixed" it, but when I got it back , it did the same thing. I sold it for very cheap a while back.
The 2nd one I gave to my brother. It has always worked fine, except when I was cleaning it one time, the piece that has the spring slide spring around it came loose and flew across the room (it broke). S&W sent me another one free of charge and it works OK. (The same piece on the glock is made of metal, not plastic). The gun is pretty accurate, and reliable as often and I used to shoot it alot.
However, I would not buy them again, and would instead get a Glock. Pay extra and get something that is worth it. I got a Glock 26 and have had zero problems with it.