OK so over the past number of years I've been using the Bartolini 5.2 harness in all the basses I've built when I wanted a 3 band EQ. For the latest bass I just completed, I decided to aim for New & Different, and dropped in the Nordstrand 3B-5B.
Both are great preamps, as mentioned above - the Bart is a bit more flavored and the Nordie seems a little more subtle - maybe somewhere in between my Audere-equipped bass and the ones with the Bartolinis. Maurilio's finding about the treble setting on the Bartolini is spot on with what my ears tell me, you really need to crank that treble (especially when using series humbucking pickup configuration) once your strings start to lose that sparkle. A few of my instruments have three-way toggles for parallel/series/single and you really hear a much more open sound without that big lower mid extension on the parallel/single settings, which can help if that sparkle is an important part of your sound. The three-way midrange switch on the Bart is nice (250, 500, 800), especially if you have a rig that really lets the midrange speak...250 gives some of the big fat bottom without being muddy, 800 for Jaco, it's a nice option.
I've only had my Nordie-equipped bass for about two weeks thus far, but I pretty much think the 3B-5B matched to a set of dual coils is a major, major win in the versatility department. Between the master tone control on the Nordstrand (ala the Sadowsky VTC) stacked on top of the EQ and pickup combinations, you can easily spin up a ton of tone types. It's a bit more complex of a setup than what you're looking at in terms of specs, but the tone sweep coupled with the EQ alone is a beautiful thing. I view the Nordstrand as a sort of a best of both worlds marriage of the Sadowsky and Bartolini preamps.
Lonnybass