The Flight Framework has the easiest setup and is a pleasure to code with. It has some nice utilities as well, such as undo/redo and a great asynchronous workflow. I recommend anyone who hasn't looked at it yet check out http://www.flightxd.com/flightframework

I hope I'm not asking for too much, but I'd like to see coverage of Parsley, Spring Actionscript, plus whatever you can on Mate.
Thanks guys!

Flex on Rails

http://flexonrails.com/

GraniteDS

http://www.graniteds.org/

You can add in your list Maashaack + VEGAS :

http://code.google.com/p/maashaack/
http://code.google.com/p/vegas/ (based on Maashaack now)

Advanced ADT (Collection, Maps, etc.) + IoC implementation + advanced event model based W3C with FrontController + eden the ECMAScript Data Exchange Notation + logging engine + Reflection .... etc.

Download the last AS3 repository version of VEGAS and try it :)

More examples in AST'r the ActionScript template framework based on VEGAS :

http://code.google.com/p/astr/

EKA+ :)

Spring ActionScript +1

I think it's important to keep in mind that just because the word "framework" is used doesn't mean you're comparing apples to apples.

There are MVC frameworks, dependency-injection implementations of the Inversion of Control principle, application development methodologies, component frameworks (hey, like the Flex framework), data abstraction frameworks, etc.

I'm not saying that everyone has got it wrong, or that you necessarily misunderstand this concept, I'm just underscoring my opinion of the importance of this concept.

All that being said, to toot my own horn, HydraFramework.com.

Backend framework for everybody who is using OSGi: http://arum.co.uk/amf3osgi.php which is based on GraniteDS
Turns OSGi services into Flex RemoteObjects