"Totally different" is perhaps a bit strong - they're reputed to have a Bill Lawrence background too -, but they are stacked humbuckers as opposed to true single coils though they sound (and are intended to sound) single-coilish, nice natural presence and harmonics. They are fine pups - perhaps not adding the most idiosyncratic tone color, but you hear a lot of the bass' natural character. On the RD, I really prefer them to the anodyne humbuckers used in the active Artist circuit - you hear more wood, less pup. I also have one of them implanted as a bridge pup in a modified seventies EB-0 and it sounds swell there, also in combination with the mudbucker, bit like a Ric Higain would, but with a wider magnetic field.
Uwe