I'm running 5.1 analog out of my Sony Blu-ray into an analog input (NAD) and analog out to the amplifiers. In this case the NAD is just a pass through volume control, nothing else.
The audio in The Bourne Trilogy is very good in DTS Tru HD, but could not tell that much difference in the DTS 5.1.
But the Sony is a 1st gen player (did a firmware update for tru HD), so perhaps it's time to go with LG or OPPO.
Again, the music on Diana Krall was much better balanced (less boomy bass) in DTS 5.1 going through the processor.
Thanks for your input!