Old Milwaukee is not so bad.
It compares pretty well with the other popular American lagers (Bud, Miller, Coors, PBR). It's nothing special, but it's at least as good as those others. To quote Jimmy the Greek from his old Piels commercials, "It's a good drinking beer."
Don't confuse it with Milwaukee's Best, which as far as I can tell is at least 75% sewage.