Not coral specifically but ive cut coral off of plugs and cut glue off of skeletons and stuff with one. My experience is that it is pretty slow going and produces alot of vibrations that the corals don't really seem to like. Ultimately I say it works, but it comes down to what your trying to cut up.
It would likely be best for cutting thin branches on sps or something like that. I think it would likely struggle cutting something with a thick skeleton like an acan. Not to mention how much damage it will do to the flesh in that scenario
I just use a diamond blade in a hand held battery operated dremel...works like a charm the have diff blade depths as well cost me a total of 23$ with blades. What kind of corals is going to be the big question.