Okay, for a moment let's step away from the hype.
LeBron -- outstanding season and THE player for Cleveland. In fact, Cleveland dumps a couple of scorers (Miles and Davis) to make sure that LeBron gets his shots, looks, etc. LeBron's numbers are quite impressive even if he is on one of the lowest teams in the NBA.
Anthony -- also an outstanding season and while Denver has more talent than the Cavs, Carmello leads his team to the playoffs. Look at the stats, Carmello isn't playing the point and with the exception of assists, is right there with LeBron in every category -- even leading in many. The difference? This kid led his team from the cellar to the playoffs. I also think that Mello is the better defender -- LeBron still has a LOT to learn about defense (although I wouldn't say that Mello is an outstanding defender).
I think there are many people who allow other factors to play in here:
For LeBron: all the hype that has surrounded him, he IS the guy for his team, he has been a fan favorite
For Mello: some hype, he has brought his team out of the cellar to the playoffs, exhibited selfishness.
I think if you can JUST look at what these players have done on the court and take away the hype with James, the selfishness by Mello -- I think you have a deadlock -- and I, personally, think the ROY, this year, should have been shared. But, IMO, you can't take the risk of offending the leagues biggest hype machine.