ActionScript 3.0 :: Open-source Flash 3D Engine Comparison?

For some reason, I'm having a hard time finding a recent, side-by-side comparison of the various pros and cons of the different open-source flash 3D engines, such as Papervision3D, Away3D, and Sandy3D. Specifically, I'm looking for comparisons in the areas of

ease of use (and documentation) performance (framerate with lots of polygons) stability (bugs, glitches, graphical artifacts) currency (for lack of a better word - is the project gaining or losing team and community members?)

language(s) used (is it in as2, as3, flash-player-10 as3?) features (lighting and shadows, import models and animations of various formats, click detection, collision detection)

This is reasonable, right? I don't want to essentially pick one at random, only to find myself in trouble later on. Working with papervision3D, I'm already frustrated by the documentation, or the in-name-only nature thereof - most functions only have headers listed and no descriptions of what they do. Personally, I like to be able to pour through the documentation and figure out how to do whatever I want, and I feel like I'm fumbling around in the dark, having to read the source and try to understand all the implementation details. Who's used multiple open-source flash 3D platforms?