I am not, generally speaking, a JB fan. That said I tend towards Mahogany body, 243/4 scale, mahogany/rosewood neck guitars. Probably not surprising.
Last one I owned I hated (but got a crap ton of tone compliments live). Swapped the mag for an A8 and was very happy for a long time.
But right now I have one in a Dean Cadillac that I just love!
At the end of the day, I really think the JB is a great pickup all around. I could play Rock, Blues, Metal, Shred. or just plain Pop with it if I wanted. I think that is one of it's real strengths. There will always be a more bluesy, metal, articulate, or whatever. But a JB is a great all around pickup period. No reason to hate it. It is the Glock of pickups.
No doubt there are places it almost always shines (Floyd & Superstrat) and places that it may be hit or miss...(All Mahogany Les Paul). But it's rarely tragic. I also think that it is fairly maligned on the internet by skewed perception. on the Les Paul deal. I bet a to - and I'll even say 80% of all JB to a Les Paul players are wayyyyy happier with their JB than the 498 they threw out. It's just here in tone snob land where we get that particular.