I’ve had my two J&D mini jazz basses for almost a year now, and they’ve weirdly become my most played basses. One is fretted, one is fretless (fitted an ebony fingerboard meant for a guitar from StewMac, a project in itself!), both have Hipshot bridges (I love these, though putting them on a bass that costs less than the bridge might be a bit foolish...), CTS pots, GraphTech nuts, shielded cavities and TruOil’ed necks. The tuners were going to be replaced, but after I took them apart, sanded the underside of the gears flat up to a high grit count and screwed them down carefully, these things have been bulletproof - they seem to be better quality than the Sire tuners on my V3 (which stripped whilst DETUNING the low B!!!). I’m still on the original pickups, they sound more than fine to me (better than the Mikro 5-string I have, that I’m getting Bartolinis for).
They’re both so comfortable to play, sound great (with the Hipshot bridges mounted just a bit further back and the fact they’re longer than the original, D’Addario EXL160S sets will fit with no wrapping issues), and are just so easy to play one finger per fret, so actually less tiring to play. If you’re after a cheap bass to mod the living daylights out of and try short scale basses, these are great for that and for little money. If you’re after a bass for your kids to play, it’s a good starting point (and you can nick it later for modding...).