It's not HD, I mentioned it on their chatbox and was met with a 'wtf omg no one else has complained!?!' type response.
I kindly invited them to right click the video stream and select details, which displayed a res of 840x620 or similar. No response.
Despite this, I'm happy with the stream on a 55 inch TV, and the frame rate is the most important thing. Certainly beats all the free flash streams, just obviously not HD. That said, some streams are better than others and I think they have upped their bit rate which makes a huge difference.