DTS HD via Multi Analog vs DTS via Bistream

I want to ask if there is a big difference between DTS HD/Dolby HD through a multi channel analog out vs DTS/Dolby through a Toslink. I know that the toslinq will not handle the DTS/Dolby HD so it will be down converted.

I'm currently running my blurays through a PS3 ( I know I'll get drilled on this) and I only have a toslink connection to my NAD m15(hdmi is only video for this model).

I'm considering on getting a Oppo 80 (if I can still find one) or equivalent player with analog multi channel out with the HD being decoded internally by the Bluray player.
I will connect it to my Nad M15 7.1 analog input.

So how will the sound compare? Is it a huge enough difference to get a bluray player with a HD internal decoder and mutli analog out?