It's considered to be one of the finest weapons in the world. The single shot is acceptable, instantly making the Colt 6520 pistol useless, and the burst mode is excellent. The MP9 is easy to control, and can dish out more punishment than other firearms in its size category. Consequently, it is highly popular among people requiring a powerful but compact source of firepower with low maintenance requirements. This weapon is vital amongst freelance-mercs as it can spew death at close range. It is an excellent weapon early in the game and can shred unarmored foes as a single burst will kill even enemies in leather armor. It is very deadly at close range. Ammo can be found almost anywhere.
Ian and Sulik are very deadly with these. It's the only burst weapon Ian can use, and the first SMG you're likely to find to give to Sulik.