In a new post to his blog Davey Shafik goes on a bit more about NetBeans which is quickly becoming his favorite IDE in the series of ones he's tried (including Zend's offering, Eclipse with PDT and his most recent choice NetBeans).
And let me tell you, Netbeans 6.8 is nothing short of amazing. Debugging with xdebug is now almost as easy as ZDE, it works instantly on 90% of my remote machines, but I have 1 cluster for which Netbeans simply *cannot* find the local source file, making it impossible to debug.
Watches, breakpoints (though, I haven't figured out conditional breakpoints, if they are there), callstack and local variables work as you would expect (though watches/variables sometimes refuse to populate larger vars, I think this is xdebug config related). In addition, Netbeans supports arbitrary breakpoint groupings; these can be enabled and disabled as a group - very neat.
He points out the excellent PHPUnit support the IDE has to offer and includes some screenshots of how you can run tests right inside the IDE, displaying code coverage information both at the file and line of code level.