I think Oregon State had a tougher schedule: they played Boise, TCU, Stanford and Oregon. Besides that, the Irish are right up there with anybody else in the country.
Our schedule was tough, but definitely not the toughest in the country. The formula is solely based on winning percentages which is really skewed. SEC West was brutal this year leaving Ole Miss as the only team unranked. Doubt our record would be the same had we been lumped in there instead of Ole Miss.