I have slotted on my car. And I have no problems. But I have been doing just the opposite for quite awhile now by only using drilled rotors on my street cars and truck. I have read that slotted rotors shave off just a little bit of the pad to keep the pad fresh. Works great for race cars, but pad and rotor life are less. On my previous daily drivers and sports cars, I have used drilled rotors. For street use, the drilled holes allow heated gas to compress so the pad stays on the surface of the rotor better. It does'nt shave the pad so pad and rotor life are longer.
I get reasonable milage out of a set of drilled rotors. They dramatically improved my trucks braking distances compared to solid stock rotors. Especially when towing a trailer. I haven't compared slotted vs drilled back to back. Just my experience with drilled rotors.
It doesn't really matter which style is on my Cuda. I don't put that many miles on, but I do use them pretty hard. Brakes are made to wear out. My next set will be drilled, if I drive enough to actually kill the current set. I love getting new brakes. Its like getting new tires. Just makes the car feel new again.