If you're going to make a statement like that, at least have the balls to back it up with some facts or proof. The only reason to do that is if you actually don't know what your talking about or you're just being a dick. With that being said, I did start pretty much this exact same thread about a week ago so if you did a search you wouldn't have had to start another one.
Im assuming this guy is referring to the natural body's conversion of T4 into T3. If I could choose between #100 T3 or #100 T4 I would choose the T3 in a heartbeat.
From what I hear and things I have been reading it is a very good combination for fat loss. I will be able to tell you from experience in a matter of days