Is there anything the Ref 50 does that the 507 does not? I am trying to decide between these 2 pieces and from the research I have done I can find no functional/performance differences between the 2 but then again I don't dig as deep into some of the more obscure functions as some of you do. I was torn between going with separates or flagship receiver and have decided for my needs it just doesn't matter. Price becomes the deciding factor. But if the Ref 50 offers a feature the 507 doesn't have then I will evaluate the value of that feature. I tend to keep my equipment at least 4-5 years so I do want the latest and greatest when I upgrade. I am not concerned with being able to upgrade just a processor later on and keeping the amp.