Considering the fact that DWUD4s' text editor isn't worthy of writing a winos obituary with, I would have to say that you'd be better off writting PHP with notepad than Dreamweaver.
Don't get me wrong, I always have Dreamweaver open because I like it's FTP client. But the only time I use it's editor is when I have a hangover... which leads me back to the winos obituary.
There are plenty of free text editors out there specifically designed for programming.
They have project managers, regex pattern matching for text replacement across multiple files and keyword highlighting so you can get a better feel for your code and so damn many other features that Dreamweaver doesn't have.
If you have DWUD4, then it should have come with HomeSite, which is an ok editor, though I'm not that ecstatic about it.
A better text editor IMHO is winedit:
http://www.winedit.com
and HTML-kit (free):
http://www.chami.com/html-kit/