Sorry, thought you'd already made your mind up from your comment in
this thread :-)
I've talked at length about this elsewhere in the forum, as has Twilight. In short:
BRIDGE:
Holy Diver has more output than Nailbomb & is much fuller & fatter in the lower mids. Nailbomb has a more upper mids & top end & really scythes through the mix. If I had to come up with one word for each I'd say Holy Diver = chunk, Nailbomb = cut. Despite being quite hot, both pickups are beautiful clean - the HD is warmer, the NB brighter, but both clean up really nicely & still respond well to changes in your pick attack etc.
NECK:
The roles are kinda reversed here - Holy Diver neck is lower output than nailbomb neck with a really sweet, bright airy clean sound. Nailbomb neck is actually higher output (& FWIW a shade more output than the Cold Sweat neck) - still usable clean & not excessively bassy, but really shines on overdriven lead work.
Hope this helps, JMO, YMMV etc....