I have tried a set extensively and I'm loving them. The closest thing I can think of, is a 59/Custom with an unoriented alnico 5 in the bridge. For the neck, nothing in the SD line comes close. I am loving this set. I have tried every BKP to date and this is one of my favorites.
'boil 'm, mash 'm, stick 'm in a stew' (strat, tele, LP), it all works great with these.
The midrange is chewy but extremely articulated. Pinch harmonics are easy and fly away. The high end is very controlable and open. The low end feels tight but doesn't overwhelm in the mix whatsoever.
The neck pickup has a liquid, flutey character I like that feels like the perfect accompaniment of the bridge. It is warm but not thick or syrupy, unlike others ( *cough* Crawler *cough* ).
I can highly recommend them but they are expensive, helas.
FYI: My favorite BKPs are the Cold Sweat set, Rebel Yell, Silo bridge pickup with a VH2 in the neck, VH2 set, Black Dog, Holydiver set, Crawler set, Stormy Monday, Mule and PG Blues. I.e.: vintage output up until medium hot. I don't go for the high output craziness anymore, for years by now I suppose.