Originally Posted by JCL

No, they don't run any cooler.

Drilled rotors were originally designed for pads that outgassed. The holes let the gases escape. No modern street pads outgas, though. A drilled rotor is structurally weaker, and therefore more likely to crack. If the rotor blank is designed to be drilled when it is designed and manufactured (ie Porsche OE) then fine, but a standard rotor that has been drilled for looks is prone to cracking.

Cooling is primarily a function of the cooling fins between the two rotor surfaces. Cheap rotors have poor cooling, OE rotors generally have the best. People can't see the cooling fins, so don't realize the importance of them.

Slotted rotors can be noisier due to the action of the slots on the brake pad, resulting in shorter pad life.