This is an awesome question. Easy answer is the one where you could make the most money. Real answer is probably college. A big time college football coach is a god in a college town. I also think once you have your program set up with recruiting and all, it’s an easier gig. Plus, college kids aspiring to make the NFL are probably much easier to coach than millionaire prima donnas.
Other college coaches that found success in the pros are Bill Walsh, Pete Carroll, Chip Kelly, Tom Coughlin, Jim Harbaugh, Bill O’Brien, Mike Vrabel and Barry Switzer. I’d chalk up BOB as a success just for longevity’s sake. IMO, the modern NFL is the hardest sport to have sustained winning because of the cap. It’s rare, but it can be done.
As for Urban, I love the guy and he was obviously great for us in Columbus. However, count me in the 2-3 year max camp. He’s going to lose interest really quickly when he realizes he doesn’t have 7-8 layups on the schedule. The NFL is a grind and I suspect he’ll go back to the health/stress reasoning when he leaves in a few years.