I've done that a few anims, but cycles Mb just looks better when i can use it. My render times aren't too long compared to the time spent animating, but if it gets really freaky, then yeah, I may use basic resolve Mb, or vector Mb, which i did in my last ahri animation
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Vector motion blur sounds promising tho! Never actually used it myself, sounds like I should at least give it a try some time.