The Glock feels to me like holding a brick and the trigger pull is not smooth. It seems to hang up slightly just before it goes "bang". That increased resistance always causes me to pull down and left.
True story. I bought a Glock because I was looking for a solid CCW piece. It's definitely not ideal for any serious marksmanship. That's why I've been looking @ Sigs (and even considering popping my 1911 cherry).
I guess I should give the M&P a shot too... Call me gay, but I just don't like the way it looks.