I considered gold foil pickups (or at least one) in my Mustang but I found them a bit 'brittle' sounding, for want of a better word - they didn't have the bark I was looking for. They look nice enough, and they vary massively. tbh the name is a bit misleading; it doesn't seem to refer to much apart from the fact that there's a gold bit on the top, which can be made of metal, paper, foil.. I gather they use certain magnets in a bar shape which gives them a certain tone. Like @Doctor J says I think it's more about brand identity... I'm all for trying new pickups and interesting takes on the norm so it's cool with me. I'd prefer a single pickup in a P shaped body, but the J shape needs two IMO!