Roku. Yes, you can watch subscriber videos. Link your account by going to
Yes, you automatically get HD (according to Internet speed) when streaming. No, you can't watch live stuff. Recently found an unofficial twitch app for Roku, but missed trying it for Unprofessional Friday yesterday. May work for regular live events. Hope that helps.
Yeah, non-premium live streams can be watched through an unoffical app. I do that whenever i'm around during a live event.
There is no current way i'm aware of to watch *live* premium content through the roku.