I fist tried Eclipse as a web development IDE a little over one year ago. At the time, I had mostly just stuck with Dreamweaver for all of my general web/PHP/ColdFusion needs. I had heard that the new version of Flex Builder was being built on Eclipse and figured to give it a shot.
I was severely disappointed initially- the IDE was slow, clunky, and configuration was a nightmare. Performing a quick uninstall and returning to Dreamweaver took all of 30 minutes. I tried installing again from time to time, but things were always the same. When JRE 6 was released, this did speed things up quite a bit and at that time I also discovered the Aptana project. Having a “web IDE” install like Aptana was pretty convenient, but I still remained solid with my regular development platform.
With the release of Flex Builder 2, I couldn’t help but use Eclipse more often for MXML editing and so became more familiar with it as a development IDE. I was still annoyed by some small things like no text drag and drop… file not associated with a project could not be opened… line numbering randomly turning itself off… but things were generally better the more experience gathered.
With the release of Eclipse 3.3 [Europa], I have to say that a lot of my misgivings have been taken care of. Not only can you now drag and drop text from line-to-line and edit files outside of the “Project” paradigm, but it is much more responsive as well. With an update of Aptana I notice that it now has an AIR plug to compile and deploy AIR apps built with HTML/JavaScript. I cannot help but wonder what a killer environment Aptana would be with MXML/AS3 support! That would be a serious development platform!