Firstly the body-shapes differ slightly. Other cosmetic differences are things like the pickguard and the metal control-plates that only J-Bass has. Then the P-Bass has one split-coil pickup while the J-Bass has 2 single-coil pickups. The neck-profiles also differ in that the J-Bass has a slimmer neck than the P-Bass.
In terms of "which one is best", it's up to the player, they are both great, just different. But the J-Bass is a bit more versatile. A lot of players get basses that feature a P-bass body and a J-Bass neck with 1 split-coil pickup and 1 bridge-position single coil to try and get the best of both worlds.
So how do they differ? What makes a player choose one over the other? The primary differences can be summed up in three areas: the body, the neck and the pickups.
If I said you have a beautiful body...
The Precision Bass looked radical in 1951. Its deep double cutaways and forward-raked design was like nothing the guitar world had seen. And it preceded the Stratocaster (which has a similar body style) by three years. In 1954 the Precision Bass, which had been a "slab" until then, adopted the contoured body of the new Stratocaster. These sculpted recessions at the bottom and top made it more comfortable to hold. The original Precision body was ash; now you can choose from models with ash or alder bodies.
The Fender Jazz Bass, released in 1960, offered players an alternative to the Precision. Its offset-waist body, which was drawn from the Jazzmaster guitar introduced a couple of years earlier, moved the mass of the body forward and out of the way of the player's right arm. As with the P Bass, ash and alder body models of the J Bass are available.
Neck and neck...
Most Precision and Jazz Bass production models have what Fender calls a "modern C shape" neck. Each model's neck is maple, with maple, rosewood, or pao ferro fingerboards available. But there the similarities end. Each neck is distinctively different to appeal to different players' preferences. The Precision neck maintains a fairly consistent thickness and tapers in slightly as it approaches the nut.
Meanwhile, the Jazz starts with its strings in a noticeably narrower spacing at the nut that give it a distinct "tapered" feel for what some players feel is easier fingering. And the fast-action maple Jazz neck debuted with a rosewood fingerboard that made it easier to manage.
With that in mind, though, a wide variety of neck options are open to today's P Bass or J Bass buyers. From Custom Shop models with a full "C" shape to Artist Series Jazz with Precision necks and Precisions with Jazz necks (as with the Deluxe Series P Bass Special), you can have the body/neck combination that suits you best.
A couple of pickup lines...
Upon its first release the Precision Bass had a single-coil pickup with a chrome-plated cover. Within a few years Fender moved to a split-coil pickup that offered a more defined and solid bass sound.
The Jazz came out of the chute with dual eight-pole humbucking pickups that gave players a wider variety of tonal possibilities, thanks in part to a softer, less spiky signal that was not possible with the P Bass's single-coil pickup. The end result was a bass some players consider to have a cleaner sound, with more tonal variation possible through use of a pan knob that adjusts the balance between the two pickups.
If you're looking at buying any of the new Fender American made basses, you're
in for quite a search. I was at GC last week and another shop two weeks earlier and could not find one Fender bass that was set up properly, even from the custom shop. The original basses, 65 and earlier were fast and almost effortless to play.
You can still achieve those results with a new one, but be prepared to try many of them.
Honestly, I would look for an American built bass made in the 80's that still has a perfect neck. If it's still good now, it should stay that way forever.
The difference in tone between the Jazz and Precision and the finger reach on the neck is the deciding factor for most players.
A well built P/J bass clone with a slick neck is by far a more versatile instrument these days.
You can have a better bass custom built for less than what the Fender Custom Shop
is charging for what SHOULD BE their standard of quality.
Thanks guys. From all your responses I've decided that what
I'm going to get is a used bass with a rosewood neck, ash body, and I'm leaning towards the Jazz Bass because it's more versatile and I don't think I know exactly what I want. I think it's one of those things where I'll know when I hear it kind of things.