3 OT games this year and 3 more decided by 3 pts or less. Utah does just enough on offense to stay in the game.
Also, Utah is more tested, having played 6 ranked teams (okay, two have dropped out of the rankings, but still) in their last 7 games. Boise's lone top 25 game was against Ole Miss, a solid loss.
I think BSU is the overall better coached team, but that Utah simply has more talent.