Blue control can win it, for a price. Masticore, treachery, thwart, etc.
On the other hand, I have a small green stompy with exactly one rare that turned out pretty well: stampede driver, briar patch, wild dogs, spidersilk armor, fog, skyshroud beasties, and dawnstrider (my one rare) are features.
Black-green was a color combo nemesis liked. Plague witch can handle swarm pretty well, and a couple big black anti-creatures (massacre, viscious hunger, forced march) will work agains the better rebels. Meanwhile, the big green creatures (rhox, blastoderm) can run straight through your enemy, or at least keep him defensive.