Frankly I think this is something you should Google and has nothing to do with 4Runners specifically. There are posts with countless replies as folks argue plain vs slotted, vs drilled, vs slotted and drilled.
My belief is if you are keeping your factory (not TBU) calipers and just upgrading the rotors and pads then buying Brembo slotted & drilled (both) with performance pads is a great combination which will yield better braking performance and cooling (eg less percieved warp) compared to default 4Runner rotors.
I had this setup for many years. Now I have the full Tundra upgrade kit with normal OEM Tundra rotors, mainly because one of my original calipers finally went out around 220K.