Lately I've started using OpenFl for my personal projects. I can honestly say it's a very good experience!
It's basicly like programming flash, but with the option to go much lower or much higher.
It can import SWF's and use them on all platforms (some platforms are more compatible that others).
The export to html5, android or flash is in a switch of a button. Exporting AIR project for android was a huge mess for me in FlashDevelop (maybe others could do it with much more ease), but with OpenFl, after installing all the sdk, ndk, ant and stuff, it's as easy as making a flash project. And even this installation is automatically with openfl tools.
Some of the language features works best only on flash platform, but the OpenFl team is working on solving these problems. For migrating from flash, this is the best solution for me.
And, of course, FlashDevelop makes it very easy