They might still be wrong - see my original post here:
http://www.chaosgroup.com/forums/vbulletin/showthread.php?72714-Vray-MB-vs-Houdini-mantra-pbr-MB&p=581287#post581287
Also, there is an option for raytraced motionblur which is off by default.Again, that doesn’t mean anything if the raytracing is for camera rays only. Also, I presume that this is a lot slower than non-raytraced moblur.
Best regards,
Vlado