Horribly overrated.
He's now 8-8 in the playoffs, and anyone who watched the games the year they went to the SB knows that he was mostly a spectator - defense and the running game won them the SB. His QB ratings that year - 71, 39, 79, 81.
He has 3 playoff games with ratings over 100, and a career rating of 85 in the playoffs.
http://www.pro-football-reference.com/players/M/MannPe00_playoffs.htm
He never beat Florida, never won a bowl game, and UT won the title the year AFTER he left.
By the way, every skill player he's ever played with was a first round draft choice - no QB has ever had the weapons he's had. (I know he played with Garcon and Collie this year, but look at all the previous years, even his RBs are all first rounders).
Just because the announcers blow him worse than Favre doesn't make him the greatest QB ever. He's very good but NOT close to the best ever.
Horribly overrated.