Tuckstir Ah so more confusing than a Confucius..
Completely! ?
I've been confussed by it all too - really just an excuse to play more guitars and find what does what, what works with what, and eventually (hopefully) what works for you (and when).
I'm torn between filtertron's and P90's atm - I've played some great P90's and some crappy ones - I like the clarity and middy-ness of them - kinda like a musclebound single coil? But then I played some filtertron's and liked the clarity and definition of them - alas, beyond my skills to exploit!
Personally, I've found that when someone say sounds like a XYZ in ABC format - generally this isn't quite true. E.g. Sounds like a P90 in a single coil size - there's a reason why a P90 sounds like the way it does and a lot of it has to do with the size/(form factor) of the pup itself - which doesn't lend itself to being stuffed into a smaller SC form factor - same for humbuckers
But, possible I'm channeling a bit of the cork sniffing purist here - which I'd like to think I try to avoid. There's many a happy accident and just because it's convention to have X in Y form factor doesn't mean it couldn't work in setting Z.