Parseghian obviously faced USC in its prime; they won 3 full/partial NCs and 4 Rose Bowls during Ara's years at ND. He also played MSU at its historical peak in 1965-1966, Purdue during its best-ever sustained run from 1965-1969, and unbeaten, top-ranked Texas and Alabama teams in 2 bowls each (going 3-1). Parseghian was 7-9-3 against teams that ended in the AP top 10.
Holtz faced Miami and FSU in their prime, going 2-2 and 1-2, respectively. USC and Michigan were top powers in 1988 and 1989, and Holtz swept both teams both years. Holtz also played 8 straight bowl games against top 8 teams from the 1988-1995 seasons (going 5-3), including 6 against top 4 teams (going 4-2). Holtz was 15-17-1 against teams that ended in the AP top 10, including 4-0 in 1988.
By comparison, Kelly is just 2-6 against top 10 teams, and was utterly embarrassed in his only bowl game against a top 10 team.