So, you've got Dreamweaver 8 and you're not sure if you want to shell out the $$$ to upgrade to Dreamweaver CS3. This can be a challenging decision. Now that Adobe has bought Dreamweaver, have they ruined it? Or is it so much better that you will kick yourself that you didn't upgrade earlier? Or something in between? My opinion: somewhere in between.
Adobe Bought Dreamweaver
No, this isn't news, but for many Web designers, this is a critical reason to purchase Dreamweaver CS3. This is the first version of Dreamweaver to come out with a full integration between Dreamweaver and Adobe graphics tools like Photoshop. Now when you have an image in your document, you can click on it and edit it right in Photoshop quickly and easily.
Better CSS Support
One of the coolest new features in Dreamweaver CS3 is the addition of better CSS layouts. They are well commented in the code, so it's easy to start understanding how CSS layouts work. Plus they have over 32 layouts to choose from in fixed and liquid designs and 1-, 2-, or 3-column formats. You can also define where you want the CSS (in the head, in an external file, or in an existing file) right while you're creating the new page.
I also really like how easy it is to move CSS styles around. When I'm testing a style, I often start out by styling the exact tag right in the HTML in a style attribute. But this isn't scalable, so once I get the style working I have to move that rule into my style sheet. With Dreamweaver CS3, all I do is right-click on the tag in the inspector and choose "Convert Inline CSS to Rule". Dreamweaver will build a custom class for that style rule or style all of those tags or create a full CSS selector based on the position of the element in the document tree.
Creating pages for mobile devices is becoming more and more popular, but it can be very difficult to design pages that display well on both a standard Web browser and a cell phone. With the integration of Adobe Device Central, Dreamweaver makes it easy to preview your pages in various cell phone emulations. My only problem is that it didn't have my phone (a PalmOne Smartphone), but I suppose I can continue to test on that browser manually.
Implement Ajax on Your Site
Dreamweaver CS3 includes the Spry framework to make it really easy to add Ajax widgets and effects to your Web pages. It's just a matter of dragging and dropping and incorporating your dataset. Spry components include: widgets for lists, tables, tabs, and forms; effects to make transitions like shrinking, growing, fading, and highlighting; incorporating data from an XML feed such as RSS or database.
XSLT Support with XML as Data Sources
Dreamweaver now has extensive support for XSLT using XML files as data sources. You can view the XML in a tree form, and then connect it to your HTML document with XSLT. This means that if you have lots of XML files in the same format, you can create a template for them in Dreamweaver using XSLT.
Better Support for Macintosh Intel Processors
If you're on an Intel-based Macintosh you'll be very pleased with the performance improvements of Dreamweaver CS3. Since it is now native to the platform, rather than running on Rosetta, it loads more quickly and simple actions like typing in your text seem to respond more quickly. According to the MacWorld tests, "updating a template in Dreamweaver CS3 on our 2.66GHz dual-core Xeon Mac Pro took just under a minute, as opposed to nearly four minutes in Dreamweaver 8." I haven't done specific testing, but it does feel faster.
Should You Upgrade
I have upgraded and I haven't looked back. I really appreciate the new CSS features and Device Central. I haven't used the Spry framework, but with the better support of XSLT I will be testing that out soon. The biggest missing piece is something that most Web editors don't do well: design-time programming. Dreamweaver CS3 is still just as hard to use live databases and server-side scripts as it ever was. However, there are extensions available that can help you out - check out the Dreamweaver Exchange.