I think Sonnen is a pretty knowledgable guy. He's also competed in SOMBO at a respectable level I believe. That said, his writing style is horrible. The man makes up his own words to sound smart. I think it's just his marketing style. Talk a lot, but don't say much.
I've seen his IOUF video and I wasn't impressed. He overcomplicates the whole grip fighting process with his "concepts". There is also a video online somewhere that shows him kickboxing or something. He looked ok, but not at a high level at all. I would expect that somebody selling instructional videos on "fisticuffs" would be a better striker. So there is definately some Bullshido in what he's pushing imo.