So I did some testing, and while I don't have the solid numbers on the bitrates, it does seem like the Amazon app on the display has the best sound and picture.
One thing that that very obvious, the Hulu "Live TV" service is CONSIDERABLY lower quality than anything that is streamed "on demand". So if you have Hulu Live TV with HBO, DO NOT watch the GoT premier "live" with Hulu. The sound drops to just "Dolby Surround" and it's probably 720p max. When you play something else, like any current episode of GoT, it's Dolby Digital + Surround and much better video.
I'm alright watching GoT on streaming since we can have friends over that want to follow the series but most of my movie viewing will still be discs. Just got the Hero blu-ray yesterday actually, looking forward to it.
Oppo 203 - PS4 Pro
Denon X4300H + Outlaw 2200 (Center)
Klipsch RP-250F, RP-450C - Dual PB-1000 Subs - Onkyo Satellites