[diamondtrim]

Sounds like the Netflix app just had better bandwidth detection and quality adjustment than Amazon or HBO. Not surprising, as the latter two are less mature apps and infrastructure built by relatively newcomers to the streaming business whose core competency is not in digital media distribution (regardless who may have built their system). Ironically, it might be because you bought it in HD that it buffers excessively on your roku, whereas it might stream better in SD.

But none of that matters, you are correct at this point that Netflix clearly has it figured out and working for you, while their competition does not. Only to say, the dynamic bitrate support is likely to improve on the other apps with time (not to mention, your internet connection is likely to periodically increase in speed for various upgrades to your equipment or your ISPs) so those issues are likely not permanent.