I don't have ProPack yet (still waiting for localised version). So I'm still wondering if the built-in MB is really usefull for me. How does the alpha channel behave, when rendering with motion blur? Is alpha blurred correctly? Or will it be even 'killed'? BTW, can you compare the rendering time (and quality) of this feature with 3rd-party programs, like Reelsmart Motion Blur, and with rendering without MB? Thanks