I don't think it's bad as long as the content is acceptable. I can't really think of a form of music that would be bad unless it specifically required some seriously anti Christian activity. So, until someone comes up with a form of music that requires using human skeletons as xylophones, or IDK, skulls instead of drums, it'll probably be all good.
The only bad thing about dubstep is it's been killing trance, and trance is awesome as it was like the natural progression of early dance music (not that I can dance mind you). This is my personal opinion. Also, it's hard to find Christian trance, so you're stuck with a lot of secular love songs (not always bad as long as there's no sexual content involved). Perhaps dubstep will reverse this trend which would be nice. Then if they could only go back a genre and give me some Christian trance well that would be sweet.