In light of the recent licensing scheme announced Flash content that uses two “premium” features, the issue that affects most of us here is that Away Physics uses opcodes while Away 3D uses Stage3D, hence anything you make is subject to the license requirement. 

But there is an alternative to Away Physics here:

http://www.jiglibflash.com/blog/2012/03/21/jiglibflash-updated-for-away3d-4-0-beta/

So for many applications where you need physics, even if JigLib is a little less performant, you may be able to use it just fine as long as you only need light physics support and don’t intend to to really push the limits.

But that brings me to the most obvious question: is Away Physics really faster?

Perhaps we could all benefit from testing this out and reporting our results?

What is your experience?

I am working on the car racing game. I have use both jiglibflash and awayPhysics.

Jiglibflash is enough for light physics usage but not enough power for heavy physics usage. (I remember I get 50% faster after I switch from jiglibflash to awayPhysics). For racing game, high fps is critical. I have no choice.

I am happy using awayPhysics now and I look forward jiglibflash improvement in future.