HD and BD are very similar in overall voicing imho. Between those two it comes down to how 'open' and dynamic compared to compressed and smooth you like your pickups to feel. The BD is lower output and so feels a bit more open and maybe has a bit more low mids and bass, the HD is a touch more compressed and smooth. But they are very close to each other. The NB is more angry, hairier high frequencies, more high mids and cuts through more, some people love it, for me it wasn't fat and warm enough, so I prefer the other two. I think that the BD is my favourite bridge BKP, with the HD very close to it, although obviously it all depends on the guitar and your setup, etc :)
