When I was very young, and knew basically nothing about handguns, a 1st gen Sigma .40 was the first handgun I ever bought new.
I had to have the feed ramp milled, it was VERY picky about ammo. Covered under warranty, right? The front sight FELL OUT. I wanted Trijicons anyway. The trigger was something like 12 lbs. I know I read that in advance, but I didn't have enough experience to really understand what that meant. After the third or fourth trip back to the smith, I started to ask myself if I really trusted it enough to stake my life on it. I sold it for a loss and was glad to get rid of it.
I take every possible opportunity to tell people to stay away from them. I have heard that all the problems I had were worked out after the first gen, but then I think to myself, "Why could they not get it right the first time?" This business is way too competitive, there are SO many good pistols out there, a manufacturer can't afford to drop the ball. They put out another generation. (Most manufactureres seem to get it right the first time these days.) Then they imported the SW99 as their own. Then the M&P. So it took them THAT many tries to figure out what Glock pretty much got right the first time.
The M&P might be miraculous. But I'm a LONG ways away from ever wanting to pick up another S&W auto. After my 1911s, Glocks, and XDs fail, MAYBE.