Does anybody know the general differences between having a MM/J setup as opposed to 2 J-pickups or 2 standard soapbars?
In my experience the MM pickup is more aggresive with alot of bite. It has a midrange bump that helps it to cut through. Think about the sound of the Music Man basses. It sounds particularly good for finger funk. The jazz is much more mellow and warm (opposites attrack) balancing out the aggresive tone of the MM pickup.
I usually favor the MM pickup for fingerstyle and the jazz for slap (just a little past center both ways).