User blog comment:Callofduty4/Favorite SMG in MW2?/@comment-1790643-20100514133852

As much as I hate being killed by them, the best SMG to use is the UMP45. The Ironsights make it easy to acquire targets, the low RoF makes it easy to track them, and the power makes it easier to kill them.

And you still have most of your UMP mag left over after killing someone.The problem with the Vector and MP5k especially is that a moving target will easily cause you to expend half a magazine, the Vector is especially bad for this,