Musclemass. I love musclemass. Mainly cause you go into an area filled with civilians, and use the attacks just below a devastator (where you press the devastator buttons but don't hold them in, the shock-wave type attacks), mainly cause you do it and all the nearby civilians explode in blood clouds.
Also, for a different situation ... muscle mass, cause it is as fast as regular attacks, but everything you do is like twice (or more) as powerful.