Hi,
my company uses haXe for production use. For programming swf content is absolutly no problem on the technical side. Using it on the server side is a little bit harder. If you haXe for PHP you sometimes have some problems with typing (this is more or less a PHP problem). The neko vm is very stable and very very fast but it takes some time to get it running with all you other server software (mysql, apache - mod_rewrite), but once you got it you it is very stable.
We used it for generation swf applications, tried the possibilies of haXe JS. Also we created socket server for a multiplayer game and start to generate all our webpages with haXe PHP or neko.
The community is very helpful, the documentation is sometimes a little bit to short.
This is only my opinion and the experiences I made.