Ball transfers?

I wonder if anyone has any experience with using ball transfers in place
of an X-Y table or casters?

When hand-guiding a machine on a free-rolling X-Y table there is some
directional bias; it wants to move in the X or Y directions and not so
much cross-ways. I'm considering picking up some ball transfers from
McMaster-Carr to see if they would be more suitable for this kind of
application. Before I spend the money on it I'm curious if anyone who's
used them might be able to comment on the idea.

Thanks,
Dave K