If you have a Mac, try a free program called YouView. Google YouView Mac. It gives you YouTube experience, but uses the MP4 files YouTube hosts for the mobile platforms. I never have a problem with YouView. Some times it's slow, but at least you can download the entire movie before watching. Also, it uses a lot less resources, 5-10% CPU vs 30%+ if played via browser. This means better battery life.

I think something like that must exist for windows and Linux, but I could not find anything free.