Customer Rating: 
Summary: Excellent upgrade
Comment: I've been using the Dreamweaver CS4 beta for almost 5 months now and find that it fits my work style very nicely. There are some obvious changes like that it now looks more like Adobe's other programs. It's not so much the similarity of looks in the interface that helps as that the working panes and panels have been integrated into a working whole on the Mac in the same way as Windows. Since I use both platforms that's nice. Since the workspace is pretty customizable and since you can save your workspaces, I can imagine that experienced developers will end up having some pretty individualized views. I originally thought that it might take some time to learn the new workspace but it's so logically designed that it seems natural.
If you hand code at all you'll really appreciate the new features. Most of my design work now is focused around building themes and templates for Wordpress and Drupal. Before CS 4 I was hand coding the sites and only used Dreamweaver as a site management tool for static sites. That is to say, not that much. There are a few new features that have changed Dreamweaver from just another arrow in my quiver to my main go to program, Live View and Related files are the two that are getting the most press. They're great but there are some others.
Live View displays a real time look at how the page displays in a WebKit browser. Since Dreamweaver now supports side by side views, on a 20" or larger monitor that allows for simultaneous windows showing the code and the results. I love that.
What makes it even more useful is the Related Files feature. Click on a server side page, like a main CMS template file and Dreamweaver will automatically offer a set of tabs for related server side files, CSS or JavaScript. Click on the sidebar or footer files and the code view shows up. Make a change and Live View updates the preview. This works really well for multi file templates on blogs or content management systems. On the down side, Dreamweaver does not support Ruby or Python so you can't use it for frameworks like Ruby on Rails or Django. Though it does work with Cakewalk, a PHP framework. I don't use ASP or ASP.net so can't comment on those or on ColdFusion.
Dreamweaver also now supports syntax highlighting for major JavaScript frameworks. I mostly use jQuery, but MooTools, Scriptaculous and others are supported too. There are some more widgets for Adobe's framework, Spry if you want some built in Ajax.
The last feature that makes a difference for me is Code Navigator. Click on a page element and you can have the associated CSS rules pop up for editing. Brilliant. And the CSS wizards seem to have been updated, too. I find even the best wizard is slower than direct coding so haven't really given that part of the program a good look.
I've also found CS4 to be both a little faster and more stable than CS3 and that's in beta. Hopefully, when I get the boxed copy, I'll experience the same results.
If you use Dreamweaver for designing visually and stay away from working in code you may or may not find the new features quite as exciting as I do, though they aren't trivial. Live View is certainly nice and the improved CSS handling should make it easy to not design with tables. The expanded Spry functionality will make it easier to add Ajax widgets to a page.
