The SMGs suck now. It takes 8-10 shots in the body to kill a guy. I've come up behind someone and full autoed into them and they've had time to turn around and cap me with 2-3 shots from an ak.
The only decent SMG I find is the P90, and only because it has a large clip. I like to flash through a door and just spray like mad when I rush through. It works well usually. Also it's good because when the guy is reaching for his handgun, you still have 20 rounds in your primary left before you have to go to your secondary.
Unfortuneately, with the addition of the galil and famas in 1.6, SMGs are pretty much useless. The galil is only slightly more expensive than any SMG, holds more rounds than all but the P90, and is much more powerful.
Shottys don't get used much at all anymore either (I've started a little comeback thing with the pump shotty and it's oh so fun), mainly because the popular maps are all medium/long range combat ones.