I think I am done with Flex / Flash Builder. I havent heard a thing from Adobe about any plans for the platform tooling and there is a continual lag in the AIR and Flex for mobile support. I mean, just recently upgrading to xcode 5.1 broke the ability to use the iPhone Simulator which took a while to get fixed. You can make the argument its a beta cycle but should that test be part of Adobe's basic tests for functionality?
I have started my trial of Xamarin and have been working on POCs of some of the mobile components that I would need to continue working like I did in Flex.
If you add things like MvvmCross to the Xamarin equation you get data binding much like you do with AS3 / MXML.
The other added bonus is that xamarin can use its own tooling or visual studio and since they are a microsoft partner they are included in beta cycles so there is less of a lag with platform features / tooling, etc.
Sure, you have to learn a bit more about developing separate UI layers for each platform but you also get the bonus of better code reuse and windows phone / windows store and mac desktop, which are things you cant do with Flex and at this rate are things that may never come.
I may still use Flex for web stuff if it calls for it but I'm betting I can do most of it in html 5.
I find it very sad that I am giving up a platform that I have been involved with for almost two decades starting with future splash animator, but I can no longer begin mobile projects that have such a huge X factor for support and compatibility down the road. At least with the xamarin price tag comes peace of mind, you get what you pay for.
Goodbye Adobe AIR / Flex / Flash