Not that this is empirical data from a laboratory, conducted under the scientific method... but:
I installed the brakes on my old Supra; I had many times cooked the brakes to the point of boiling the fluid and billowing smoke out the wheel wells, at the track. We bagged those brakes so bad, the front rotors were completely trashed with radially aligned thermal cracks all the way around them. The front pads were cracked pretty bad. But even though physically the parts were pretty rough, they worked flawless. Sitting in the driver's seat, there was no pulsation, no pull, the pedal was reliable and firm (once the boiled fluid was replaced of course), and provided good feedback.
My '05 Limited has brakes installed at Toyota, with all Toyota parts, etc. I had the wheels off a few weeks ago and all the parts look like hell. The rotors are completely bagged and all 4 are ghosted repeatedly. And it drives like it too. Pulsation under braking, that sort of thing.
The difference is the bedding of the brakes. When I bed brakes, I do it Stoptech style... cook them slowly and gradually, then cook them REAL good. Mechanics seem to think that they go out and do 2 or 3 hard stops and they're good... but that will actually **** up all the rotors real nicely, doing that. If you come to a complete stop at all before the brake pads are properly bed in, it'll leave a cute imprint of the pad on the rotor (visible or not), and there's your high spot. Depending on materials and condition, this may machine out, or it may not.
Obviously you don't want to drive around with beat up brakes, but they will get in pretty rough shape if they're not bed properly.
I'm confident to say that the piss-poor bed in procedure that's followed by many mechanics is a 'make-work' operation, to ensure you'll be back in 20000km for new brakes because you can't stand the shudder/pulsation under brake load.
My 3rd Gen had 100000km on the front pads with plenty of meat left, 210000km on the rotors and still in spec, still true, and drove as expected.
Point I'm trying to hammer home is if you're going to put good parts on it, bed it properly:
Stock Brake System Bed-in
You only get one chance to bed them properly or you're stuck with what you have. The purpose of a brake pad is to be rammed against a cast iron plate spinning at high speed and produce heat as a result. If you can cook the brakes once and they never work properly again, then those pads were crap or proper bed-in wasn't performed, or both. Regardless, the point of a pad is to create heat, the point of a rotor is to absorb and dissipate it.
