Well here's a quote from the horses mouth himself..
CRIS COLLINSWORTH (FOX)
"They're all still alive; that's the problem. How about the Bengals? Seriously, it can't be Pittsburgh because it never wins the AFC Championship Game at home. Oakland lost it two years ago the last time it had a chance to win at home. The team that appears to be the hottest right now is Tennessee, and it's playing so well it could win anywhere. So I would say Miami. The Dolphins have the best home record of all the AFC contenders at 7-1 and they're only 2-4 on the road. For a team that plays in the warmth of Miami to go north for games, they just don't play well. The flip side is the cold-weather teams that would have to go and play in the heat of Miami. The Dolphins have been notorious lately for not being able to get past the divisional round of the playoffs. If they get home-field advantage, they'd be far and away the favorite to win the AFC."