I'd say its a lemon, possibly one of the worst weapons in the game. Due to the penalty to hit if you charge it up, you're more likely to miss your shot and just dial up your heat. Thats fine on something with TSM, but there are far better ways to do this.
Sure at full charge it can be a head capper, but you've got +4 to hit, and even at short range, good luck with that.