I bought a couple of the ceramic ones.
Hear some (lousy player, sorry

) demo clips:
https://soundcloud.com/fngasser/datb.../sets/dat-bass
The bass is the one pictured (so it's bridge and neck positions, not MM sweetspot). Passive vol-vol-tone-tone circuit. Recorded direct from the line out of my GB Shuttle head.
For US$30 each, I'm more than satisfied with them. That bass sounds thunderous, and cuts through a two-guitar band mix like a razor. Lots of "finger noise", ghost notes jump for lively funk. I love this bass, and I'm thinking of putting in a preamp in and get the full potential out of both pickups at the same time (i.e. eliminate the usual output drop due to loading)