I have both, the B5D's are good and for the purists they effect the polar pattern of the mic less as there is the air gap around the mic and the B5Ds are pretty good in light winds, the A81WS screens will hold up in higher winds however and dont effect the sound or the pattern much as far as I can tell. I am about to order some windcutters for my Shures for those really wild days.. I record for film too so sometimes I need get useable sound even if its hurricane force.
JC