It all has to do with adaptive streaming. Netflix uses it. HBO Go does not which is why it is unreliable.
Also Netflix uses Microsoft Silverlight which streams way better uses better codecs as HBO Go uses crappy Adobe Flash which I don't think can even do adaptive streaming and who knows what codecs they use.
You need to subscribe to HBO anyway and your cable/satellite/telo company needs to support it but as to pay for it ala-cart it is not worth it well at least right now.
Charter Spectrum powered by Earthlink.
My Router: Netgear R7000 - Advanced Tomato 3.4-138 K26ARM USB VPN-64K.
My Primary Streaming Devices: Fire TV Box (2nd Gen), Roku Premier (2016).
Cats are the best pets.