He teaches a prosperity gospel. I don't know if I'd call him a fraud, but his ministry is very light on the gospel. I just checked his web site and to go to one of his revivals there's a $15 charge. On the front page there's no mention of Jesus, but advertisements for several of his books.
Just in my opinion, I'd be more inclined to listen to Tony Robbins than Joel Osteen. At least Robbins gives practical advice.