Is YUI3 ready mature enough? What are its advantages and disadvantages compared to YUI?
@Corwin is incorrect about files changing on the yui.yahooapis.com servers -- if you use the YUI 3 PR 2 release from our servers, those files will remain there even when subsequent releases come out.
It's true that the API will change some as we move toward beta 1 (scheduled for June) and then to GA. We will undoubtedly make changes that will require your attention and time as you upgrade. That -- and the fact that YUI 3 doesn't contain all of the functionality of YUI 2.7.0 (the current release in the 2.x codeline) -- is the primary reason to hold off right now.
You can learn more about YUI 3 and how it's different from 2.7.0 here:
http://video.yahoo.com/watch/3711767/10207432
We're using YUI 3 on the next version of Yahoo's homepage. You can read about that here: