I've dealt with Marshall quite a bit during the past couple years, and while I can't say he's the most enjoyable coach, it's also a situation of him not trusting a lot of people. When he trusts you, its a different story.
He's always made it clear that he's going to do what's best for him; the only difference from a lot of coaches is that they hide it. He's a very smart guy, and he knew that for Winthrop to get the hype it needed this year, he was going to have to be very outspoken. In turn, he knew it was what was going to help him the most.
I've heard some funny stuff re: an interview he had with an SEC school a few years back, essentially where he told an AD that he "didn't really need to interview." Needless to say, he didn't get the job.
And yes, most people think his wife is a pain in the ass.
The CofC thing was his only real mistake, simply because he listened to too many people telling him he was going to be a god there, realizing it really would have been a step down.
And as much as some people might want to think so, the MVC is a huge step up over the Big South. The league was 29th in RPI (out of 31 leagues and the independents) last year.