On my 05 speedmaster the fronts lasted about 9,000 on stock pads and rear lasted bout 4,500. Im now at 19,500 on my speedo and second set rear pads look good. My front rotors need to be replaced per 5mm min thickness(going with some floating rotors)but the sintered metal pads I put on ftom NB.com still look good. I was harder on my brakes the first 5,000 miles, especially the rear, compared to now. I don't have much stop and go (CA center third lane rider when necessary)and I use gears to do most slowing for stops.
As everyone has said its hard to say its not your riding style that mostly affects the brakes. The sintered metal pads sure decreased the amount of brake dust on the wheels especially the front.
I got my rear pads changed out just in time to not get into the rotor with metal on metal. I swear the pad was paper thin on one side.
Thats too bad you got into your rotor. They aren't as cheap as my old ford rotors.
Speaking of rotors, do any of you all have experience with the floating rotors. I believe they are less than new stock ones.
Gary
