Television evangelists are the same as everyone else, flawed. Some are truly believers and some aren't, not my place to say. I don't care for Joyce Meyer (her voice rubs on my last nerve), but I gained knowledge from reading her book...or at least a new idea of what could be true. Tammy Fay and her husband were pretty laughable, but some people did gain understanding from their teachings. The list goes on and on...
I'm not a fan of any television evangelists, but I am not their target audience either. Whether or not you like someone, you can still learn from them if you stay open to learning about God. God can use anything to further His purpose.