Andrew Johnstone has posted some of his experience he's had developing with one of Zend's latest offerings - Zend Neon. Neon is the Zend project to bring robust PHP development functionality to the community on top of the Eclipse platform.
I've been using Zend Studio for Eclipse (beta) for several weeks in a rewrite of a framework and numerous sites at work and overall I really like the IDE. Its got some great features and being based on the eclipse project makes it really extensible and customizable.
He happy overall with the IDE but has come across some bugs in his time developing in it (nine of them) with issues ranging from the SVN functionality and samba out to small syntax sorts of things (like the auto-formatting).