Brown. Of course, belt colours don't mean all that much in MMA, but in general, his grappling is very solid.
P.S.: I usually don't post in this sub-forum, but I always enjoy reading it as a more intelligent version of the other fight discussion sub-forums on this board. Personally, I find this card very difficult to bet on, as the odds seem to be pretty spot on now and quite a few of the fights will probably be decided by variables which can hardly be predicted at the moment. Romero was a great option when he was around +250 or more, but that line evened out as well. Anyway, good luck to everyone!