I think it's an oversimplification to say that any amp with a flat frequency respone and low THD sounds that same as another other amp. I'm sure some amps do sound the same, but there are a lot of them out there. I don't want to get into an argument about it but I shake my head every time I hear it.
Don't do it Shane, just accept that all amps sound the same from $98 to $98,000. No such thing as higher quality components, or DACs, or DSPs making a cleaner signal path unless it can be measured in THD. Just accept it.