I hate to say it, but the top of the line roku, with a wired Ethernet connection, or wireless AC from your router, if you have one, seems to get the best through put from Netflix/Hulu, at least for me..
The worst throughput, at least for me, always, is from the native Sony TV version of these apps..I have a bd790 BR, and even that gets better throughput than the tv natively..
This suggests that the CDN that Jerry describes are the culprit; enough blame to go around. I forget the details but when I first got the set i was experiencing Apple TV had "great" bit rate for Netflix, but not the TV. As both where on the same network, either the TV HW or SEN was slow. Your experience also suggests SEN. Not sure what an Oppo would go through but seems like direct to Netflix, but the Oppo post I quoted would suggest that, given all that, the Apple servers either get favored treatment, or act like aggregators (Akema) and actually improve Netflix, or something. Heavy on the "or something" I suppose :-)
But I have done the obvious thing and flip between them and there are differences in streaming, and PQ. BTW the TV app might have had better PQ or before I figure out to use the "Crackle App" to adjust internet PQ setting, just snappier settings. SO many variables. Remember when a TV was just a display :-)