Just curious, but why are SDs so much better than just regular humbuckers?
It's all about preference.
They are regular humbuckers. Just a brand name. Some are active pickups and require a battery. I've never actually tried any myself, but they are suppose to be pretty good.
they are humbuckers, or single coils, it's just the brand name
well if you're happy with the pickups that came with your guitar then they won't do much for you. but seymour duncans are built to a specific spec and quality so they will be decent. also theres a huge variety of them if you want a different tone than whats in your guitar now.