As for Starfire I models, with only one pickup: I currently own a 1970 SFB-I with the neck position Bisonic that holds a whole lot of sentimental value. I used to own a 1966 SFB-I with the "sweet spot" more-toward-the-bridge position Bisonic.
I think that there is no "better" between the two. One test that I would suggest that may help you determine which you would like more, is listening to a bunch of Jefferson Airplane and Grateful Dead recordings (both studio and live) from 1968-1970. If you like Starfires and Bisonic pickups, you will likely find all of the bass tones to be excellent, but if you prefer the Dead bass tones, you're probably more of a neck position Bisonic guy, as Phil seemed to lean more in that direction. On the other hand, if you dig the Airplane bass tones more, you are probably more of a "sweet spot" Starfire guy, as it seems like Jack Casady had a tendency to dial in more bridge than Phil... but that's not by any means a perfect science, since both had various modifications, crazy/unique amplifier setups, and variables in the mix, but I'd say it's a good starting point.
Of course, the best case scenario is having both 1960's variations in front of you to A/B them, but that is a very rare opportunity for most.
In regard to 2-pickup models, I have played several Starfires and owned a JS-II bass with dual Bisonics. They undeniably have more flexibility in tone than a single-pickup model, but that's not to say they can nail the exact tone of one of the single-pickup models... and I'll stop myself there before I ramble on and on