Apple released the GM seed of Xcode 4 yesterday which adds to my hopes that we will soon see the final general release. Unfortunately it is still pre-release software and hence considered Apple Confidential Information which makes me uncomfortable discussing the details.
The frustrating thing about this confidentiality clause is that I see many of the big Apple news sites breaking it on a regular basis. It seems that as soon as a new iOS beta appears for download the major news sites are in a race to provide details on anything that is new. Anyway a couple of things I think I can say:
Ready for Prime Time
Unlike the previous Xcode 4 developer previews the Xcode 4 GM seed can be used to submit iOS apps (and Mac apps) to the app store. This means that you can actually start to use Xcode 4 for production work. If you have never downloaded and played with one of the Xcode 4 previews I would say that now is the time to give it a test drive.
I have been installing the Xcode 4 releases in a separate directory (/Xcode4) so that I can maintain multiple versions and switch back and forth. I do not see that approach changing for a while. Support for Xcode 3 will be dropped at some point, maybe with the release of OS X 10.7, so now is definitely a good time to start getting familiar with Xcode 4.