Well, Obito was shown to act impulsively without fully considering the consequences throughout the manga, and is currently matched against a proven genius (Kakashi). I think that in a conflict between Kakashi and Obito, Kakashi should win, if he does not run out of chakra (which he should not if the 9T resupplies), simply because they both have same eye, Obito does not seem to use his Rinnegan much if at all, and Kakashi is simply smarter.
What is not clear to me is, how are Madara and Obito controlling the juubi - or are they even controlling it? I think they are just letting it have its way.