Marcus
I've had a couple of Jaydees; the first one (an early Supernatural with Saturn inlays, tailpiece etc) wasn't so successful; someone had shaved the neck down to nothing and it was very unstable. Also it was very heavy, and when I sent it to John Diggins for a setup he changed the pickups (which he said had lost a lot of power); unfortunately when it came back I didn't like the tone!
My second one was a white Mark King with dot inlays and the funk groove; that was a great, great bass. Unfortunately it was again too heavy and had to go back to the shop. When I bought it I played it back to back with an 1980 Series 1 Alembic and it was certainly comparable.