If you are looking for the same screan shots, then you have already found them. With the exception of the processor, the firewire and the maybe the digital tuner, both cards use the same DACs, and the same hardware in ending signals out to a TV. The only reason for getting the 8500 is if you want to play games like Aquanox at higher resulutions, and if you want to incorporate the firewire ports. Other than that, they are very simular cards.
If it works for you then don't fix it.