Well, since I got my RS525, I had to start thinking about a replacement neck pu. I've liked hybrid pups ever since I made one from some Ibanez pups I had lying around - the presence, harmonics, crispiness, and 3Dish qualities sold me on the idea.
So, I got a used Jazz and 59, and swapped the slug coils, keeping the stock polished A5. This guitar has push/push pots for series/parallel. I'm playing through a Marshall 50w AVT and treble booster.
For me, the Jazz/59 hybrid is the donkey's bollock$. In series, it's got just enough syrupyness to state its claim as a neck pu, but with more presence, overtones, and spontaneity, for want of a better term
- lots of character. Now it's possible to play open chords under gain and still hear them. In parallel, it's snorting, rude, and has lots of clang, like something between a Strat pu and a P90
- I nearly flipped out when I first switched to this setting.
On clean, it's very balanced sounding. Overall, it's restored my faith in neck humbuckers - many don't sound bright enough to me, and I do prefer singles in the neck, but this thing is very nice indeed. While the 59/Custom is now in production, you'll have to make this one yourself if you want it. For me it was very much worthwhile - killer neck pu with a lively articulate tone.