Is NekoVM interesting? As you said, using it for Flash is the most interesting part, as it's a good alternative to the official tools, especially on platforms Adobe doesn't like that much. Yet compiling to PHP for the web (page/service) part of it seems oddly wrong to me.
JavaScript/node would be another option, but something more native might pique my interest.
I agree that the PHP portion seems wrong - but it is in active development and I know a lot of people are indeed using that feature - so while it might not be my personal output target of choice, it does get used.
The biggest benefit of all this is a build once, deploy multiple architecture, so if you are a Flash developer, you can also target iPhone or C++ for desktop, or other outputs with slight code changes.
When developing for php or any target, you still need to be aware of some of the quirks:
http://haxe.org/com/quirks
These are familiar to php devs, but maybe less so for people who just want to work with haxe on php platforms.
JavaScript/node would be another option, but something more native might pique my interest.