Hmmmm, My Yamaha RX-V1500 is supposedly "THX Select"...
Not sure if it's certified, or if it just uses the THX decoding specs...
Does my Denon POA-5200 (THX certified) sound any better than my Behringer A500's???? No. In fact the behringer has much more headroom, so it might be fair to argue that it would sound better over a wider dynamic range...