Interesting debate on where Clemson stand - I'd say they're right smack in the middle. Not quite Alabama level, but still above the rest though closer than some want to admit. If you want to say Clemson is in the tier with Oklahoma/Ohio State etc - they're leading that tier by a couple scores.
Clemson has been to every Playoff - winning one, losing to Bama twice (once as Runner-up, once as Semifinalist). In their playoff runs Clemson has beaten - Oklahoma, Ohio State and Notre Dame. Their regular season losses though not bad in score have been to average bowl teams - Pitt and Syracuse.
Ohio State has the one title where they beat Bama and Oregon, but they have that no-show in the Semifinal against Clemson as well. They also have terrible score losses to Iowa and Purdue - both bowl teams as well.
Oklahoma has 3 Playoff trips and is 0-3. They're the class of the Big XII, but the Big XII has shown to be the worst conference result-wise in the Playoff Era.
If I'm ranking programs on tiers I'd have:
#1 Alabama
#2 Clemson
#3 Ohio St, Oklahoma, Georgia
#4 Notre Dame, Washington, etc.
To me Clemson is smack in the middle of Bama and the next 3. Oklahoma is closer to ND and Washington than they are Clemson though.