What is the benefit of using the Haxe version of Starling over the AS3 version:
The main benefit is that you can target new platforms (such as HTML5) while still being able to compile to SWF/AIR.
What are the down sides of using the Haxe version of Starling over the AS3 version:
It has missing features.
It is a port, so new features can take time to port over, or are simply missed.
What is the benefit of using the Haxe version of Starling over OpenFL.
Starling is hardware accelerated, so it utilizes Stage3D while running in AVM2, WebGL while running in HTML5 and OpenGL while running in C++. OpenFL on the other hand still relies on CPU driven flash displaylist and HTML5 canvas. (Even though it has an openfl.display3D package, it doesn't utilize it for these platforms).
Does Starling Haxe have any dependencies.
Yes, it relies on OpenFL's "openfl.display3D" package, along with things like errors and events. This means that these packages could be pulled into the starling port and the rest could be removed, but to be honest I'd prefer to retain the dependency and benefit from future updates to OpenFL.
Does it compile faster/slower than the AS3 version.
This all depends on what platform you are targeting, if you're targeting Flash/AIR or even HTML5 then it'll compile in much the same time... C++ on the other hand is SLOOOWWWWW.
Can I debug as easily as the AS3 version.
Again it depends what platform you're targeting. If you're targeting Flash/AIR then yes debugging is more or less the same, you'll even be able to use scout to profile you're application. Debugging while targeting HTML5 is pretty easy as well as you can map back to the haxe code, but it's not quite as nice... C++, hmmm not really sure what the deal is there.