On 3g seems to buffer maybe every 35 mins or an hour 4G you might want the extended battery but 4G does play hq I also have hbo go and it freezes alot but pausing and hitting play fixes it. I would say netflix is very watchable on the thunderbolt and I love it also I'm stock not rooted with latest ota
Works fine for me on 4G and WiFi, haven't tried it on 3G. Sound occasionally gets out of sync for some reason, pausing and starting back seems to fix it.