Hi Laurence,
Ive still got my DYN-B, and i use it on about 75% of my gigs. Ive had it for about three years now and its been brilliant for me. It took a little getting used to at first, placement of it, how to eq it etc, but its pretty indispensable for me. I love how it comes on and off in seconds so it dosent bother my bass. Also, its brilliant when you have more than one bass and can use the same pickup,or touring and using different basses.
I know of a few people who have tried the DYN-B and really didn't like it, but one of the best live sounds I've heard is Reid Anderson who used it with blended with a Realist. It seems like it dosent get on with certain amps, i used to used an Acoustic Image and it couldn't get a good sound with the schertler. Ive got incredible results plugging direct into the back of the QSC K10, that sounded awesome.
So, it seems like the DYN-B is a bit of a moody bugger, but if you get lucky with the right bass and amp combination, its easily the best pickup option I've encountered.