What are the leading CF alternatives available for Coldfusion + Flex integration?

(Possible alternatives being Adobe's CF, Bluedragon, Railo, etc.)

What would you use for Coldfusion middleware if you had the following requirements and major considerations:

• Flex front end (w/remoting via AMF)
• Free (or low cost enough for a non-profit side project)
• Large enough community and resources online to find assistance when needed
• Maturity (and confidence that a particular version 开发者_StackOverflow社区of CF isn't going to turn legacy any time soon)
• MySql database

I think Adobe CF would tick all your boxes except your 'free' requirement. We use BlazeDS and Flex with it, it's mature, well supported and has a large friendly community. In short it works great.

However, in terms of the licence cost there is an argument that CF has a lower cost of ownership but if paying anything is a big no-no, then I'd look at Railo - it's pretty much up to CF 9 standard, it's got paid support if you get really stuck and it has some active forums.

Hope that helps.

PHP is an another alternate for a back-end. It talks to MySQL and can do remoting with Flex. It does require a bit of configuration to get remoting work, but it does work.