One that Eclipse does that is really useful and PhpED doesn't do is to show the phpdoc comments for an object or function when the mouse hovers over some code that invokes the function. This useful because I don't always remember the exact invocation syntax for a function and having this popup as a tooltip type text block save a lot of time bouncing around in the code.

Hmm, as I see phpdoc comments are there...

and there

Ah, I see that the tips popup when I'm typing a function name. I had been expecting that if I hovered over an already typed name that I'd also see the tip popup and that doesn't happen. Granted, it is more useful for it to popup when first typing in the code.

I do, however, sometimes change the calling characteristics of a function, then update the phpdoc comments, then go look for the places where the code invokes the function. In this situation having the phpdoc popup when hovering over the name is a useful way to remind me of the changes that I need to make in the existing code to match the revised calling interface.

you can easily call up the tooltip even on pre-written code.

If you position the cursor within the function brackets, then hit Ctrl-Shift-Space, the tooltip appears.

Hope that helps, only just found this out myself when browsing the forums.