I checked it out this morning while enjoying my coffee: http://dynamic.abc.go.com/streamin.
The quality is not quite what you would get from cable. Sometimes you barely notice compression visual artifacts but with any high spacial frequency stuff it is noticeable. However, actor’s faces are rendered clearly. Try it yourself and see if you like it.
I bet that the bandwidth costs are high for ABC because they are not taking advantage of UDP multicast or IPv6 multicast technologies. While the commercials are limited and not annoying it would be good to have an option of paying (perhaps?) $0.50 for a anytime one-time view of a TV show without commercials.