slotted/drilled brake rotors

I do not have them. I would guess that they make no difference unless you're racing down mountains towing a trailer with the brake controller disconnected. For a normal street vehicle they are not going to have any positive effect and most likely will have a slight negative effect as there is less surface area for the pads to grab.

All that being said, in reality you probably won't notice one bit of a difference positive or negative except that your wallet will be a bit lighter.