All I know for sure is that year after year the biggest bucks I see aren't in 21 or 30, even though I spend more time there than any other unit.
I've heard good things about the later hunt in unit 44 south of Eagle, and I have seen lots of pictures to back it up, but the winter we just had may have an affect for a couple of years.
Unit 61 has a very consistent record for producing "book" bucks, both typical and non-typical. 61 is a huge unit and access is good to lots of public land, and now there are 4th Rifle season tags which can only mean that the herds are doing well. It would take a hell of a winter to damage the herd there much, so it can be a good bet year after year. Within an hour and a half from almost anywhere in the unit are hotels, restaurants, hospitals, meat cutters, and sporting goods stores should the need or desire arise.
Mesa and Montrose Counties have more B&C entries than Rio Blanco and Garfield Counties; for that matter, Mesa and Montrose have more B&C entries than almost anywhere else in the state.