Ohio State is 3-3 in its last six bowls, upsetting Oregon 26-17 (+4) five years ago in Rose Bowl. Oregon is 4-0 in bowls since losing to Auburn in national title game four years ago; their last three bowl wins were all by 18+ points- they crushed Florida State 59-20 in Rose Bowl.
Oregon's loss was October 2 at home to Arizona, a weeknight game; in nine wins since then, Ducks scored 42+ points every game, scored 50+ in four of nine- they're 8-0 vs spread in games where spread was less than 20 points. Buckeyes were underdog in three of last six games; their only loss was Sept 6 at home to Virginia Tech.
Buckeye QB Jones has only started three games, but is hardly a typical 3rd-string QB; he is much better than that. Mariota won Heisman has 40 starts under his belt- he rates the edge here.
Freshman WR Carrington (failed drug test- weed) is out for Oregon; he was stellar vs Florida State, with two TDs and 150+ receiving yards, so thats a problem for Ducks.
I'm not sure Meyer is a better coach than Helfrich, but he's done more as a head coach, including winning a national title, so he rates the edge here. Meyer is 8-2 in bowl games, Helfrich 2-0. In combined eight years at Florida/Ohio State, Meyer is 2-2 vs spread when the underdog.
Pac-12 teams are 6-1 this season vs Big 14 teams; they're 4-3 in their last seven bowl games against Big 14 teams.