Apple's Xcode IntegratedDevelopmentEnvironment, a rewrite of InterfaceBuilder/ProjectBuilder for MacOsx 10.3.

http://www.apple.com/xcode/

When released it had several interesting features, including:

* Distributed builds
* Edit and continue
* "Zero link" (during development libraries are only linked as needed at runtime)
* Predictive compile (compiles changes in the background before programmer invokes run)
* "Smart groups" (like iTunes smart playlists, basically saved on-the-fly searches)
* Pretty
* FreeAsInBeer
* Uses GnuCompilerCollection and GnuDebugger underneath

----

How does its code manipulation capabilities compare to, say, EclipseIde? Refactorings? Code completion? How about JUnit integration?

Xcode 3 implements some refactorings, but only for Objective C.

Xcode doesn't implement any refactoring tool, and IMHO, the editor is sluggish and quite unusable (buggy display, buggy keybindings etc.).

Code completion, on the other hand, is very polished and extremely usable. Xcode complete code with placeholders, such as [doSomething with:<# arg1 #> and:<# arg2 #>] (it's a method call) allowing you to complete and code very fast.

Since version 2.1, XCode ships with standard Unit''''''TestingFramework''''''s for CeePlusPlus and ObjectiveCee, and sample project build settings for adding UnitTest''''''s for your application build process.

InterfaceBuilder (shipped with XCode) is the GUI tool to design GUI, and is extremely easy to use and very powerful.

To sum up:
* XCode build and project management features are excellent. eg. you can use SubVersion, CVS or Perforce to manage your rcs.
* InterfaceBuilder is very well thought out.

----

FWIW, I haven't noticed any bugginess or sluggishness with the editor. Sure, I'd rather use Emacs, but Xcode's editor seems to be as good as any other built-in IDE editor I've seen.  (The fact that Mac OS X supports many Emacs keybindings in text fields makes me a happy developer.)

Its CVS integration leaves a lot to be desired.  It doesn't handle the nib files generated by InterfaceBuilder, which are a pretty important part of an Xcode project.

--KrisJohnson