An AV '57 goes on the internet for $1499.99. The Classic 50s is $749.99; a Seymour Duncan Quarter Pound will add $64.95 and a tweed case, $149.99, for a total of $964.93.
What does the extra $535.06 buy? Alder or ash body instead of mystery wood, nitro finish instead of poly, and pickup and bridge covers and a retro strap, all with a case that's a bit nicer than the "vintage tweed" one. (Of course, the fact that the Classic '50s is MIM versus MIA for the '57 means the price will be higher -- but that's not part of the debate, and, in fact, I've owned several MIM Fenders and each one has been a gem.)
This is not an academic exercise: I gigged with the Classic '50s for a long time before its slick finish finally turned me off. Once I got my hands on the AV '57, the Classic '50s never left its case again, and is here only because I'm waiting on payment from a buyer. As I said before, the Classic '50s is my favorite bang-for-the-buck P, but that doesn't make the A '57 overpriced: you get what you pay for. The superior feel of the '57 is well worth the extra amount -- and, you'd be hard pressed to find an equivalent bass elsewhere for the price.