So many people blogged about it already (time difference, and fun dinner last night, so I am late :) that I prefer to just point the reader to the best possible source of information: Scott Guthrie’s blog.
It cannot be stressed enough that this release is for developers only. It might very well be the last release before the final is made available, so it’s a chance for people with Silverlight content to update their code. The public runtime will not be updated to RC0 automatically. So do *not* publish RC0 code to your web servers yet, because it will break the user experience!
I played with these bits quite a lot and they’re really good. Many bugs have been fixed, and many corrections have been added to make it more compatible with WPF, which is really a must. Also added are some new controls (check Scott’s blog for more details).
With that milestone, the Silverlight team did a really great job. The final version is getting closer and that’s really exciting!