I've been to Tom Henry's place near Orlando, I went there for the journeyman's exam prep. Anyway I met Tom himself onsite but his son did the teaching. I really enjoy his books but I have an exam prep book from Mike Holt as well. I'm not sure whose style of writing I prefer, on one hand I like Tom's because he seems to anticipate the questions an inexperienced or lesser educated electrician may have and explain things in such a manner that they can understand. Mike's writing is more, I think, to the point and I really like his diagrams, you really can't go wrong with either author.