For the most part, slotted rotors on street cars are just for looks, since the rotors are never brought up to a high enough temp, to where the slotting is needed for venting and cooling.
I on the other hand, have a back road i to take to Vegas. It is curvy as heck, And even with traction control disabled, it still kicks in non stop from me throwing my little bread box thru the twisties as fast as possible can. I brake VERY aggressively and enjoy a very spirited drive on that back road. I believe i fully utilize the function of a slotted or drilled rotor during those little stints.
But your correct in that a good set of after market pads will usually do the trick. And that is where my current set up is, as of today. As for my old crappy slotted rotors i just took off,.... well, we're gonna find out how well they hold up to a 30-06 round
Cannon