ESPN has Mariota as the Heisman leader:
http://espn.go.com/college-football/heisman14/
Comparing Mariota and Barrett stats:
Completion %, M - 67.1%, B - 64.0%
Pass Yards, M - 2,780, B - 2,356
Pass TD's, M 29, B - 29
Rush Yards, M - 524, B - 771
Rush TD's, M - 8, B - 9
Total Yards, M - 3,304, B - 3,127
Total TD's, M - 37, B - 38
These are nearly identical stats, yet Mariota is #1 and Barrett is #8. I would also argue that Barrett has meant more to his team than Mariota. My point, ESPN is stupid.