Hello,
I've been coding in php5 since it was in 'larva' stage back in march-april 2003. Since beta1 I did some nice and complex projects in it, and now since rc1 is out, it's pretty stable (regardless of what you might say). I run the daily cvs version on both windows with apache2 as a module and linux with apache1&2 also as a module. PHP5 runs like a charm. Errors are very rare.
Also, RC means no more language modifications (like the removal of namespaces or additions of keywords etc.) so PHP5 *language* support could start being implemented by major editors/ide authors.
Even if php5 has still (and will always have) bugs to solve, an object/class browser, exceptions support and everything else that's new in php5 as language structure can be easily and *safely* implemented in the next version of PHPEd. Maybe even a class/object builder; support for built in classes; support for the Reflection API; etc. Exceptions handling tools/browsers are very welcomed by me

. All these don't depend on the number of bugs php5 has since it entered RC stage.
Of course that's only my opinion and if nuSphere doesn't agree then I'll continue using my jEdit which is almost fully configurable for all my php5 needs but lacks some features that i always liked in PHPEd. I'm sure there will be others that will jump to offer support for php5 ASAP (e.g. VS.Php from jcx.software). In any case I'm looking forward for the next PHPEd releases supporting PHP5.
Cheers,
Bogdan