I havent had much success with the ndo_IDirBlur macro on this site. It doesnt seem to blur anything in a meaningful way.
ReelSmart Motion Blur is fast and works well with vector blurring but their motion estimation engine sucks. One thing to keep in mind however is that just like depth based blur/defocus, motion vector blurring in 2d creates artifacts on edges. This might or might not be a problem depending on the nature of the motion in a shot. There are various pre and post processing techniques that can be used to reduce the problem but I havent found a way yet to solve it.
I wrote a macro that provides almost exactly the same results as RSMB (its just slower) but my last employer denied me access to it when I left (Its a shame because I am not sure that he understands enough about compositing to be able use it). If enough people express interest, I will take the time to re-write it.
