I have the Magicshine light. I'm just taking my chances that the battery won't explode in a ball of flames. It seems fine so far.
But it's too bright to be shining into people's eyes on the MUP. I always leave it on the lowest steady light setting, and that's plenty. If there's not much ambient light, and I meet an oncoming rider I will dim the light by partially blocking it with a couple of fingers.
I've been nearly blinded by an oncoming bright light, so I don't want to do it to anybody else.