After you have the P-bass, a J-bass is not that big a difference. Sort of like moving from Keokuk to Scranton. And a Ricky 4001 is like moving to Pluto.... And a Fender of either stripe or an approximate simile can cover every single kind of bass gig there is, albeit sometimes needing a pedal or two to goose it, while a Rickenbacker is wildly inappropriate for about 2/3 of the gigs out there, not just in looks but it just sounds too damn weird. And there isn't a bass player over 30 or under 70 who isn't either lusting wildly, uncontrollably (yet secretly~depravity is just more fun when repressed) after one every time he even thinks "fish"
http://www.youtube.com/watch?v=UBmUX74aME0
or, like many of us, he fondly recalls a 4001 as one of the "ones that got away." There was a period before the reissues where they were going for just about the down payment on a nice car, and it was sort of hard to argue even with yourself that it was a "good backup." But lordy, what a wonderfully irresponsible anti-bass-part wankfester.... They've always remained a relatively tiny, privately-owned company remarkably uninterested in pandering to the public and/or spoiled rock stars, which at least partly explains why people like John Entwhistle and Geddy Lee spent so much effort trying to make other basses sound like Ricks.