If you're an iPhone developer (or a Mac OS X one), then you're using XCode. Recently, Apple released XCode new version (4), introducing a lot of improvements. I list just the more "impressive" and useful.
RefactorRefactor is one feature I loved in Netbeans and I'm happy to have (finally) on XCode. Select a class name or a class property, right-click and choose "Refactor": XCode will search that word, how and where is used and will replace it, saving a lot of time and boring debug sessions.
New InterfaceXCode 4 comes with a new user interface. Still based on Aqua, it looks like iTunes and it's more "rational" and ordered. Even targetoptions are subdivided with a drop-down interface, making easy searching a specific option.
Embeded Interface BuilderThe interface builder is no more a stand-alone program: now it's a "feature" of XCode. Clicking on a interface file it will open inside the SDK, showing all informations (connectors, widgets, ecc.) on right side.
Drawbacks - HeavyweightObviously, there aren't just good things: XCode 4 is an heavyweight program: on my Mac Book Pro it eats 173MB and slows down my system. It's no a so drammatic, but it's boring.
Drawbacks - New ConfigurationDo you remember how you sign your App to submit it to App Store? Well, forget it. Now the procedure is totally changed. Somebody says there's from a long time, but I seriously don't remember it. I don't like the new way to configure build and distribution. Maybe it's better, but it's certanly very different: a "soft" way to learn it would be useful. A good step-by-step guide was written on Stack Overflow.
Drawbacks - ImmaturityXCode 4 comes with a lot of new features. New features means less tests. Less tests mean more problems. I have many examples: with XCode 4.0 was impossibile to upload new binary with the embeded Application Loader. It gives an error related to com.apple.transporter.util.StreamUtil.readBytes(Ljava/io/InputStream;)[B.
I downgraded it to 1.3 version (as you can see here).
Another one was some crashes. Another one is when you "delete" a file from class tree: it's really deleted. No hopes to recover it, neither looking in trash can.
Another one is the mysterious "removed references" in a project. I can't understand why, but almost all references were deleted on a project. VERY boring!