Tanner is ahead of Taysom in the mental aspect of the game. You don't get through as the top guy at the Elite 11 camp without a sound knowledge of the mental game. Tanner showed this last season and it's the biggest reason he was so successful.
If Taysom's primary was covered he had a tendency to bail out. This is partially not his fault as his offensive lines, with the exception of last season, were lackluster. However, other than a decent half against Nebraska he really didn't prove that he's ahead of Tanner mentally.