cheap pads have more carbon in them.. carbon is like a filler, so basicly cheap pads dont stop as well, dont last as long, and produce a lot of brake dust. honestly i say buy the best ones because if it stops 5 feet better, it could save you from hitting someone and to me 20 extra dollars is well worth knowing that i stopped as good as i could. now heres how it works. the pads squeeze the rotors and thats what makes it stop.. kinda like brakes ona bike. the rotors should be smooth and shiney.. if the surface is not smooth technicly you end up with more surface area and your brakes stop better, but most people think its absolutly horrid and you have to turn them / replace them. I would only turn them if its badddd scoring, or you are getting vibration when you stop. ps ceramic pads are made out of a better material, and stop even better especially when heated up, they dont fade (mush pedal) but the price you pay is that it eats your rotors faster meaning you will have to probably replace rotors due to the thickness after probably 4 sets of pads. but you get premium stopping and almost no dust..