It as effective as shooting from the him should be. Works in fast reaction close quarters run in but your not shooting across the level at the hip that would be fucking annoying. If u cant aim then you suck.
The games biggest issue is spawning and game match-ups. spawns to close to enemies way to often. Game matching needs help if you on a shit team and keep getting annilated the system doesnt break up teams to even them out on past matches stats