I have both the small and large ones from before Sorby became involved.
I like both for traditional spindle work, and use them for this purpose
almost exclusively. They don't split wood, allow a lot of control of
drive/slippage and make it convenient to dismount and remount blanks.
About the only disadvantage is if a lot of slippage occurs, the multiple
teeth can bore a ring into the end not unlike the rim of a Forstner bit
(if not too deep, this can actually increase holding power, though).

They are not a good choice for roughing out most large bowl or hollow
form blanks as they don't allow pivoting of the blank to adjust for
figure, nor do they have the gripping force to deal with large out of
balance blanks. For that you are best to use a BestWoodTools 2 prong
Texas drive center.

Lyn

wrote:
just curious how you like them. seems like an interesting drive center.

best
M.