it rocks! Thats as much as I will really say at this point in time. But definitely the best php editor I have ever used. It has alot of cool features that are actually useful and not just fluff, like setting bookmarks, function completion, and i can even ctrl+click functions and constants to find out where they are declared anywhere in a project or file. Basically its all the good stuff from MS Visual in a php-centered product. I recommend it!
http://www.zend.com/store/products/zend-studio/