Both are extremely smooth movement and great looking textures, both of these efforts are amazing for Flash is at this level. I would say Paul Spitzer’s paradox papervision3d based engine is still a little more responsive and the textures have such good baked lighting that is is very smooth (he posted recently on some internals and usages of media in the engine). But from these two engines and iterations you can see that the FPS engine in Flash is not too far off.
Although there used to be crashes with away3d it has really improved and this is very smooth. My processor was actually quite chillin’ with all the software rendering carpet bombing from software rendered 3d in flash. But it really is starting to get much better with optimizations to flash this year and papervision, away3d and sandy getting more mature and further iterated to greatness.
The away3d sample if you walk through the rooms also has an interactive button, opening doors, room transitions (and if these are dynamic) a decent room engine with pretty sweet load times since the whole thing is under 300k.