I really like the .40 on paper, but that's about all. It seems to me that the designers just didn't leave enough margin for error in this round.
Also, it's not as well shaped for reliable feeding as most other rounds, it's not as accurate (IME and depending on who you talk to) and it's not cheap to shoot. I got a friend who claims 10,000 rounds through his Glock .40 without one failure, (yea right) anyways...
Who knows though, a couple years from now I may be the .40's biggest fan....