[RayBarbeeMusic]

I recently had all 3 in the same guitar back to back so thought I'd post impressions in case anyone finds it useful.

Air norton S: This should be called Norton S as it does not have the very bright highs of an AN in the bridge.  Highs are rolled off and there is a very pronounced low mid and mid hump like a high output humbucker.  Still tracks fast picked runs at lower gain settings and artificial harmonics are easy.  If I were playing heavier music with scooped mids and more gain, this would be a great choice.  As it is, I'm using low to mid gain with a lot of mids, so it is maybe a tad dark and has too much of that tube screamer ish mid bump.  When in parallel with the middle pup, quack is good but not in the knopfler/ krantz range, and far better than any full sized bucker with similar tone.  This is due to the short length of string samples compared to a full size and the position/slant.

Pro Track:  Do NOT let the tone chart fool you.  This pickup has a ton of high mids and a neutral bass, which make it come across as a very bright pickup, and to my ear somewhat grating and thin. IMO best used in a dark sounding guitar with less than a 500k volume pot. 

Chopper:  Winner for me, as usual lately.  These are ending up in my guitars where I put a humbucker in a strat bridge.  Sounds like a very nice PAF, despite DiMarzios description.  Articulate but not piercing highs, solid but not overwhelming bass, sufficient mids to be vocal but no mid hump.  I've been experimenting with about 30 different PAFs lately and the chopper fits right in that tonal family, and honestly a better sounding PAF than many full sized buckers that cost multiples of its price. 
Quack in position 2 is very good, far better than any unsplit full sized bucker and right up there with a hot single coil bridge.  This is really a fantastic sounding PAF for a strat bridge position that requires no mods to routing or pickguard, and no splitting to quack right in position 2.

[darkbluemurder]

Thanks, Ray, this is very useful, even though I only have experience with the Chopper so far. But I considered at one time replacing it with a Pro Track but I am holding off of that now as it does not appear to be warmer than the Chopper.

Cheers Stephan

[fommof]

I've been using the Pro Track and Air Norton S since last December in the bridge position on my two #1 strats and while I can't compare them with the Chopper (as I've never owned one, I can compare them with the Tone Zone S though) it kinda seems we are on the same page.

All these tested on two theoretically identical guitars (same brand, model, specs, setup etc.) but I know for sure that acoustically they are not the exactly the same, one is more alive (or less dead) than the other. Also, nowadays, 95% of the time I play clean, and when I say clean, I mean CLEAN, no blues clean, no semi-clean. All these pups are great with dirty and heavily distorted sounds (a bit different to each other though) so I won't get into any more details on that.

I kinda agree with you on the Air Norton S which has been my favorite for some months now. I would describe it as a very balanced (no excessive mids, no ear piercing highs, good full bass but never overwhelming) and probably kinda dull for most out there but this is exactly what I like most with this pup. Great with 500K pots, I could run it all the time with the tone full on. Great with 250K too but that would make the tone pot kinda obsolete or at least a lot less useful. With my setup is by no means a high output pup regardless Dimarzio's specs, I would classify it as a mid output. This pup is currently on the least "alive" strat of the two. Two Fast Track 1's are a great match for the neck and middle, that's my favorite setup.

Now, the Pro Track. Although it's not a mid-freq monster (personally I hate these pups) it's way more alive and cheerful than the Air Norton S which to the most out there I suppose makes it more musical and singing (for lack of a better word). Certainly more middy but not annoying, sure more highs but again not piercing and the right amount of bass so it sounds big. Great with 500K, I do usually back off the tone a little bit, for my taste I would say (and I agree with the OP here) that it's even better with 250K (less need to roll off the tone) but hey, I kinda like every single Dimarzio SC sized humbucker I own better with 250K especially if I don't want to mess up with the tone pot too much or at all. Pinch harmonics are easier to get with this one. Again, with my setup I would classify it as a mid output too, it sounds more high output than the Air Norton S but that's because of the more flattened ANS's mids. This pup is caurrently on the most "alive" strat of the two. It might sound strange but I found that a Cruiser Neck and Cruiser Bridge in the neck and middle pos respectively is a great sonic match (a little bit more difficult to match the volumes but it's doable).

Both pups (and the Tone Zone S) have been tested on both guitars, the results were similar but significantly "amplified" on the most "alive" strat (in theory I should install those the other way to give a bit character to one guitar and remove some from the other but it was my conscious decision not to).

That's my personal and obviously very subjective experience with those, take it with a big grain of sallt as I spent the last 27 years playing strictly low output SSS strats, never liked or could even use the bridge pups for cleans (now I use them 80% of the time).