Before I can answer, it would depend upon the definition of "success" you want to use. Super Bowls? Championships? Winning seasons? Hall of Fame career? Longevity? Overall record?
You establish the metrics and we will apply it to both of them and see which one measures up the best.
For the second part, I'd say O'Brien is working out well for BC. He's still employed there. BC's standards of success may or may not be what WVU expects so as long as he is employed he's ok. For Edwards at ASU, not so much as he was fired.