slotted/drilled brake rotors

The 2nd generation Dodge diesel trucks were hell on front brakes. A good friend, fellow crew member and respected independent repair shop owner was putting a Hawk pad and slotted rotor on the fronts and nearly doubled front brake life. Stay away from cross-drilled because they like to crack.
Randy

There are many differing opinions on their effectiveness on anything but a car doing constant hard on and off braking.
For my money, they don't show any ability to stop a heavy vehicle during a panic stop. And in fact some tests have showed they don't perform as well in that kind of event because the holes represent a loss of surface area on the disc.
If one has to do frequent hard braking going down a hill then maybe they make sense.
I don't use my brakes that way so I would not have them.

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.

Yeah, they do. On a race car. On your Tow Vehicle, not so much.