Don't know if this has been mentioned yet but this post is from last October.
MLB.tv did something similar a year or so ago where they switched from something that is actually meant to play video (WMP) to something that I can't really tell what it's meant to do (Silverlight). They had a similar deal where once you opted in you couldn't change back to WMP. They had (have?) all the same kinds of problems with it not working for people or just being worse quality.
Now this has happened a second time with a completely separate content provider and I don't know what to think other than that Silverlight is synonymous with crummy picture quality and choppy playback.
Any program which runs right is obsolete.