Over the past few weeks this has gotten considerably worse for me, and now it's pretty much impossible to watch any premium content. I've tried the Xbox One app / phone / PC (Chrome, firefox, IE, etc.) with the same results.
What's interesting is that the buffering seems exactly the same no matter what quality settings I choose. Low quality buffers no less than high and HD, same in both progressive and HTML5.
I know at one point @wcarle was working on a thing that would help pinpoint and auto-detect video issues, has that been implemented? Or is this something that is being worked on in conjunction with akamai? It's getting ridiculously bad, and while my connection isn't the best out there it's got no issues playing HD content from anywhere else (Netflix/Amazon/Movies Anywhere/YouTube/...).