In no particular order, I've used Barcus Berry B3150, Underwood, Rev solo, Nanoflex, Fishman BP100, KK golden trinity mic, and a kk bassmax.
Of the afforementioned, the only one I got on with was the Barcus, a very true tone but reliability issues coupled with having to strap the units preamp to the tailpiece meant goodbye.
I currently use a Gage realist (original version) and a Fishman full circle into a Raven labs PMB2 preamp.
Was intending to try out the new Gage Soundclip but have heard a few rumblings about build quality issues.