I think in boxing the obvious level of skill in punching is much higher than in mma. But cage fighting has more excitment more top guys fight each other and because in mma gloves have less padding there are better kos. I believe that in the future mma will draw more fighters and the skill level across all ranges will get very high there will be guys who have generally world class skills in all ranges. the fact that white people do better at mma will draw more fans To the sport than say a hispanic fighting a african american that has been the trend in boxing untiil the accession of calzaghe pavlik etc
MMA has one big promotor and at the same time sanctioning body in ufc wich give it the advantage of deciding who to give title shots and if the fighters wants more money no title for you, thats why i prefer boxing even with all the different titles its still a WORLD sport. Imagine if Don King or Bob Arum would also be boss over the only titles in boxing.
UFC is far from the only promotion in the world, though. Most of the best heavyweights aren't in the UFC.