Like Peter, I love the Flash IDE and I also started using it a long time ago (I think in version 3). I have developed complex apps in it (mostly AS2). I still do basic AS3 and all AS2 projects in it.
Let me save you come confusion. We may use Flex Builder to write AS3 code but we seldom use the Flex framework. That's one of the reasons for the re-naming to Flash Builder. The Flex IDE is a more robust coding environment. I mostly create ActionScript Projects, export assets from the Flash IDE as swc libraries. You can also link your library items or document classes to classes coded in Flex. There's a lot of back and forth between the 2 IDEs. Flex Builder shines when you start using a lot of frameworks (like Away3D, Tweenlite, FLAR, etc...) and for code hiting, completion and live error checking. Control + Space becomes your best friend and I find myself doing it in the Flash IDE! It also manages your import statements. The Flex framework is another beast. A rapid application development framework. It's easy to spot with the un-customized components (like the default pre-loader) and adds 100kb to your swf. I have used it a few times but its mostly overkill for what I do. I have created entire complex apps that were 40kb! So 100kb for a few buttons and binding is not really logical. The main issue is that there isn't a single integrated workflow between the Flash IDE and Flex (Flash) Builder. Let me save you some time: there will probably never be a single integrated workflow. Adobe is patching some workflow scenarios but the spectrum of apps developed on the flash platform is so wide that there's no magic solution. It's touch and go, trial and error. I still think that a flash professional should be able to code in the Flash IDE. It's like bootcamp. Give Flex Builder, Flash Builder, Flash develop or FDT a try and see which one you like. Keep in mind that's its not simple but it's very well documented. Of course, and this is also why people love flash developing: we help each others out! So you can find answers online to most problems. Cheers, Jerome.
