Well, you need to be in it to lose it. Any game with playoff implications is big, including the playoff games themselves. That Marty is 179/120/1 in the regular season and 5/12 in the post-season is pretty telling to me. Besides that, he is 0-2 against Levy in the playoffs, so how would you rate him above Levy?
And what you'll find in general is that you can go to any NFL city and they'll tell you they have/had a coach that was worse. Levy in Buffalo, Cowher in Pitt, Reid in Philly, Grant in Minnesota...Schott would rank among them if he managed to get to the "Biggest Game," but he'd have to win "big games" to get there...