I've borrowed my friend's crossbow a couple of times that had a red dot scope on it. I wasn't too impressed, but it seemed to get the job done. I took a 6 - point buck one year with that crossbow/scope. At close ranges it worked, but if I had one on an ML I'm not sure I'd want to shoot much farther than 75 yards or so with it.

Personally, I wouldn't buy any type of scope that requires batteries to work - I don't trust technology that much.