Xcode 4: the super mega awesome review:
diting: Xcode gets brains There have been many criticisms of Xcode, especially from those coming from other platforms. "The UI sucks", "the key bindings are different", "it doesn't give me a blow job upon a successful build". Most of them are silly complaints that boil down to either a) Xcode is different, or b) an inability to check if a preference exists. However, there are lots of valid criticisms about Xcode, especially with regards to code completion, refactoring and other similar features. All these ones boil down to a very simple fact: Xcode doesn't really know much about your code. Thankfully Xcode 4 is more than just a pretty face, it also has brains.
Also, screw you Apple for not allowing free account apple devs to download the new version and selling it for $5 in the app store, that's just lame :(