what's up with pick-ups

No this isn't a rediculous question. I've been playing bass for almost a year. I had a P-bass, i hate Fender, and now i've that magnificent Ibanez btb 405. Now both of them came with the factory pickups and i've never played it without any other ones. I'm sure they make some difference but after hearing about 30 different types of pickups i was kind of scared away from a purchase. I need some help.