I'm not a fan of grinders myself. A guy at work was using one, disk shattered, caught the metal, jerked out of his hand, grinder flew into the air and landed about 2 inches from his crotch with the remaining disk piece about 2 inches into his leg... fat and junk was oozing out.
But then, he was a very very stupid guy, and insisted on holding the grinder with 1 hand so he could "feather it" for a nice looking cut. Also, the safety guard was taken off. :Wow1:
If you have to cut anything other than just metal though, I'd go with the sawzall.