I suppose I should sound off on this one. Granted, I'm not in Japan yet, but will be later this year.
Right now I'm teaching at the Korean equivalent of an eikaiwa, and it's not a bad gig. I don't want to get into eikaiwa teaching in Japan, though. I may keep teaching, but I'd prefer to get out of the "money mill" type situation. Working at a normal school wouel probably suit me just fine.
Then again, there's always the student visa option. I've got lots fo GI bill cash to spend, and more education is usually a good thing.