I've heard from a couple of users that tried streaming on Dtube that the experience isn't as enjoyable as it is on Vimm.tv. I haven't personally tried streaming on Dtube yet, so I can't tell from my experience but, from all of what I have heard from people who did stream on Dtube is that Vimm.tv is generally a much better option than Dtube.
This might change in the future as Dtube just released the streaming option not so long ago, but for now, Vimm.tv is definitely a better choice.