I consider myself a serious PHP developer. I've also been using Zend Framework for the last 2 years, the last 6 months heavily.
It's always about personal preference. Eclipse / Zend Studio and other PHP IDEs will always have more features for a developer over something like Dreamweaver. For me at the moment none of those features weigh more than a convenient ftp client built in.
If I run into a larger project that will take longer before being able to go live to make small updates, then for me Zend Studio would be my choice.