Successful referees adhere to the credo of the Milford Academy: be neither seen, nor heard. This makes writing praise for a referee quite a difficult task. Saying that Herb Dean garnered the title of "Best Official in MMA" because he screwed up the least seems to be underselling Dean's qualities as a referee and the difficulties of the job at the same time.
Dean does one thing extremely well: He makes strong, confident decisions and sticks by them. It's OK for a referee to be wrong. It's expected, and it's appropriate to acknowledge your mistakes in retrospect. A referee can never appear indecisive in the heat of the moment.
Take Yves Lavigne, for instance. Yves is a pretty good referee when you look at his total body of work, but he'll never live done the massacre he forced Matt Brown to inflict on Pete Sell at UFC 96. Brown beat up and dropped Sell early, causing Yves to step in to stop the contest 20 seconds into the bout. Or not. Sell stood up, Lavigne second-guessed himself, and Sell endured another minute-plus of punishment. (Mike Goldberg, of course, praised Lavigne's decision-making in the heat of the moment.)
Full results after the jump.