BJJ very good if you are staying on the ground. personally I would not want to stay there in a real altercation, but I love watching a couple BJJ practitioners work. its like watching a really intense chess match! a lot of skill and thinking to win. besides the conditioning that is killer for most BJJ practitioners!
I just would prefer the JJ version, they do not stay down but again its what I would choose for me. But then every art has something they do in an interesting way. different doctrine and different strategy, and tactics to get to the same place.
only so many ways up the mountain. sooner or latter you end up in a similar place. most of the sport oriented ones are more for one on one though, and most of the older ones do take into consideration that its often not one on one in a self defense situation.