I know it's been a few months from the last response, but I feel like I should still reply in case you/someone else is still interested in a better Youtube app.
Viral HD Youtube Popup Player is the best Youtube app I've found for Android, far better than the official app. You can actually choose what quality video you want instead of HQ/HD and not HQ/HD, which is something about the official app that really annoys me. Also it doesn't shove recommended videos in your face when you start it, it instantly shows your subscriptions. The player interface also has much more usability (eg. changing the brightness/volume and being able to lock it) and it also has a neat feature to play the video in a popup window while you do other stuff (which isn't very useful in most situations really and you can disable it in the settings if you don't use it) or you can just have the video play in the background (which is really useful in case it's a podcast/music video).
It does have some bugs and missing features, which I'm sure will get fixed eventually, but in general the app looks really good and polished unlike most other unofficial Youtube apps.
(I was going to put a link to it in the Play store, but since I can't just search for Viral HD Youtube Popup Player and you'll find it)
PS. I've no idea if it fixes the buffering issue, I just had to share it since it's fairly difficult to stumble upon it in the Play store and it's just so good that it deserves far more than 100k downloads
