There is not much left to say about the Seymour Duncan SH1. It is one of the most popular replacement pickups; especially when it is desired to replicate the well balanced sound of the the legendary PAF humbuckers of Seth Lover (the name is due to the bottom sticker "patent applied for"). For many guitarists this pickup is still the best, no screamer, it is way too classy to be that, ​​but it can sing like no other pickup. Particularly finicky musical gourmets attest SH1 even a touch more authenticity compared to several competitors - but clarification to that question could probably only be found by means of an AB comparison (which is very complex with pickups) and even then, certain judgments remain simply a matter of taste. In any case, a hot tip!
The SH 1 B59 is particularly suitable for the bridge position, especially if you want hear the guitar sound as much as possible (as said, it "sings" even with moderate distortion). Therefore, it is ideally suited for installation in Single Cut types, which innately deliver enough pressure and sustain. In those cases, a too violent pickup would rather causes damage anyways.
The (slightly louder) bridge version can also be used as neck pickup in combination with high output bridge pickups, for excellent results.