MarioD
I also have NI's Vintage Organs and although they are decent my go to B3 sound is still NI's B4II! It's a shame they discontinued that one.
YMMV
B4II was (still is) excelent. The B3 sounds are at least on par with Vintage Organs. The transistor organs in VO give it the edge, I tend to stick with VO because I worry some update will cause what is now very old and unsupported software to stop working. That's probably paranoid, but.
I also use Sampletekk's Tonewheel for really gritty sounds and Sounddust's Hammr for its special character.
GSI's VB3 is also highly recommended, if they had not taken so long to get a 64 bit version out I would have bought it. Now I think I have things well covered with the addition of Melda's vintage rotary Leslie simulator which addresses some of shortcomings of Kontakt's rotary.