I have had multiple JB's, as they came stock in my favorite type of guitar, the USA Dean Hardtail. I have disliked most of them, too upper middy for me and lack of bass. In one of my Hardtail's however, it actually sounded rather good, even though I ultimately replaced it, I wish I would have kept that one. It was a circa 2002, maybe earlier as it came in a guitar produced in January of 2002. It might have been a 2001, regardless.
I also acquired a very early model JB-D, before there were any markings on the baseplate, so very early production. It has a similar character but a very different overall tone than modern JB's. Officially, nothing has changed with regard to materials in production, but I can tell you from direct A/B comparison that the old JB sounds very different. It has the "sweetness in the upper register that people talk about, but the upper mid spike is not overpowering. I think is has better lows than current models and an overall more organic feel.
I've found the same to be true with other "older" SD pickups. Maybe the wire manufacturer is different or the magnets were sourced elsewhere or the bobbins are somehow different.... screws/slugs/spacers....who knows what all could have "changed" even though the technical specs remain the same. SD was a much smaller company then with more intimate processes.... dozens of possible factors. What I know is that 80's and earlier pickups sound different and in many cases (to my ears) better.
YMMV will vary of course and these are just my opinions, but whenever I get a chance to buy a vintage SD pup model that I would use, I grab it.
To the original question, I like the JB best in strata style bodies with bolt on necks. I like a rosewood neck to help add some warmth. It doesn't suck with a maple neck in something like Alder or Mahogany or Basswood.... something not so bright. But plenty of great songs were made with JB in Ash with Maple board, so there you go.
