Highly over rated as a dangerous civilian killing tool, but great on the batllefield if it's in a weapon of sufficient size and weight for the average soldier to use. There is a reason why the M16 is no longer full auto, 1st two rounds are ok, the rest are up in the sky. The SAW is a different animal altogether, enough wieght to be controlable firepower that stays on target. Even SMGs require considerable training to be really effective. A combat shotgun is more devastating than an SMG in most urban or jungle situations. SF and Swat use SMGs because thay have the training to put rounds on target, thus limitiing collateral damage.
I would much rather face a gang banger with a full auto AK than a 12 guage loaded with 00 buck.
Now for sheer fun, everyone loves to rock n roll on full auto!