I'm not 100% sure about the Darkstar in this bass. Now that I've heard some sound clips I do prefer the sound of the Model Js, but I absolutely LOVE those pickups. The DS just seems more suitable for the vibe of the tele bass though.
As a point of reference, one of my basses has Darkstar pickups in Fred Hammon's preferred position, which puts the pole pieces fairly close to a typical J+J setup, while the other one of my basses has DiMarzio Model J's.
In both cases, the basses are 34" scale, alder body, Status Graphite carbon fiber J necks, both are completely passive and wired straight to the jack.
Some differences to note before I give you my thoughts: One of the basses has Hipshot single-string saddles, while the other has a Gotoh 206 bridge. The Model J's are wired such that the bridge pickup is in series with itself and the neck is in parallel with itself.
With all that said, this is how I'd compare my two basses that have the pickups you're wondering about:
The Model J equipped bass has more deep low end extension and a bit more upper treble response. It has less mid content, to my ears from about 300hz up to about 1khz (ballpark). This bass has comparable output to a passive MIA Fender Jazz Bass.
The Darkstar equipped bass has less deep bass extension and a slightly more muted top end. It has a lot more going on in the mids, and the upper-mids/lower treble is noticeably more aggressive. This bass has substantially higher output than the Model J bass.
Of the two, I prefer the Darkstar equipped bass tonality whenever I'm playing in the context of a mix. Despite having less going on in the deepest parts of the bottom end it sounds quite a bit thicker, while the more aggressive upper-mids tend to cut through a dense mix quite effectively. The upper treble extension of the Model J bass tends to get lost in a mix and becomes moot. If I'm playing alone at my house I almost always go for the Model J equipped bass, as it has a better bedroom tone. The tone of the Darkstars is definitely not at its best when it's solo'd, but in a band mix they absolutely kill.
Good luck!