I'm new to disc brakes, like my first set of BB7s are in the mail new, but I've been researching them for a while and have been lusting after them for a month or more, and I'd like to see what people think about the different rotors available.

Do they actually make a difference? Will a rotor with more vent slots cut in it brake less but cool better and warp less? Setting aside size, are there rotors/rotor materials which perform significantly better?

I'll be using stock 185mm roundagon rotors with my setup, should be more than enough for the mostly XC riding I do, but if I were to ride more aggressively (my new parts are already doing this to me ) would there be any benefit to going with clean sweep or other rotors?

Also what makes centerlock any better than the 6 bolt IS? I understand it's different and proprietary, but why even bother?