Hi there, I have a 5 string JJ version that I got second hand for £1000 around 2005, a bit too much maybe but I don't regret it. It belonged to my former teacher and for 5 years I longed for it.
It comes in lovely CAR with rosewood fretboard, the neck and body are maple as usual. Very light, indeed, and the slimmest neck I've had. It's glossy finish and the slightly unusual profile makes it a bit slow for me, compared with my other basses, but it is not an issue. Mine doesn't have a head dive, in fact it is probably one of the best balanced basses I've seen. The neck is very stable and you can have a very low action so it is very comfortable. Regarding the sound, I think it is amazing, with the two Bartolini J-style pups and the two-band preamp. The downside is that it has very little output for an active bass and nowadays I feel a bit lost if I don't have a mid-freq pot to fiddle with. Mind you, every time I record something with it it comes incredibly clear and well-defined on the mix... I heard that now they come with an Aguilar preamp, I'm looking forward to try one...
All things considered it is a great bass, perhaps "Jazz Bass on steroids" is a good definition for it. Outstandind build quality, 9/10 for me there. 7.5/10 for the sound. If I had the money, I'd get a soapbar version.
Cheers.
Pablo.