At the risk of repeating myself, JD is an underrated and an underappeciated pin.
Those that I have seen for sale sub $2k tend to have faded cabinets, missing topper,
and no Deadworld mod. Certain parts for this pin can be extremely hard to find and
that includes an original topper. You can buy a replacement topper for around $200,
but it has a different look from an original if that matters to you. JD playfields tend to
be in pretty decent shape since they were not overplayed back in the day.

I also know from experience that a JD can be a bit of work to get "dialed in", but once
you have it is a nice pin to have in your collection.

I would say a nice, fully functional JD is worth at least $2,300, but that is my opinion.
That is still a heck of a bargain seeing what the average price of a nice pin is these days.