Quality of the HTTP feed was great
I have a lower-end FiOS connection and 802.11g networking, and this stream played in full screen on my 2 year old 15" MBP with 10.6 beautifully. I know I was watching that stream because I used Inspect Element. There was some pixelation at times, but not like other streams I have seen.
I think they used this event to demonstrate the capabilities as well as test out their own delivery mechanism. So far, so good I say.