Flex Beta 3
For anyone following Flex, beta 3 is now available.
From my experience, Flex Builder is much improved but there are still many quirks with it. There were quite a few Actionscript 3 language changes, but the documentation on them is good. My biggest complaint so far is that many MXML files in a Flex library project are not being handled properly by the MXML Editor which results in a complete lack of code assist. The same MXML file in a Flex Application works fine. I've not completely figured out why some of the files are so broken, especially when they seem to work fine on another user's system.