Any issues? Does it replace 3.2? Appreciate the help/insight.
As long as Xcode 4 is a developer preview instead of a supported release, you are taking a big risk if you depend on Xcode for your livelihood. If you are interested only in hobby work, then the only thing you have to loose is a little hair (yes, there are several outstanding issues in preview 3). Once Xcode 4 is released, I think it provides many compelling features and I will happily move my development efforts over to the new version. Unlike Windows/Visual Studio, Xcode releases are not tied to operating system or library versions, and the Xcode team has made it so that versions 3 and 4 play very well together. So you can use either Xcode 3.x or Xcode 4 interchangeably.