You have to consider 1. where Herbie's heart is, 2. where his paycheck is, and then, lastly, 3. who his audience is.
So after consideration, he: 1. Is a Buckeye. 2. Gets paid by everybody's favorites, the worldwide leaders, and 3. This is the tough one.
Herbie is the one who seems to get his mind closer to reality as the games get closer to kickoff. As much as everyone wants to say that he picks against tOSU to seem unbiased, he uses his head and will be just about the most accurate analyst around when it comes down to it. I think he is very good at not portraying himself as an all-out Ohio State homer, when it would be very hard not to, with as much Representation as he must be riddled with.
ESPN has most likely afforded him a very comfortable lifestyle, with which he has used to create just about the most desirable job in sports, if you ask me. The dude flies all over the country, lives and breathes college football for a living, and is paid to do what most of us wish we could do for free.
As far as the National/Local media differences go, you have to go back to who he works for. When I lived in Columbus, I used to keep my radio on 1460 am regardless of day, time, or anything else you can think of. I heard a lot of what the folks complain about as far as him switching his mindset. Is he going to go on national TV to tout how awesome, overlooked, and under-rated his Buckeyes are? How far does that get the guy? He plays to an audience that largely cannot stand the Buckeyes, or at least feel that their team would throttle us. Once he gets on Columbus radio, I feel that's where the real Herbie is. If he calls the Bucks to win a game locally that he previously stated otherwise, then I would tend to lean to the local side. He simply knows how to do it.