Since I have been using Centric rotors, I have only had 1 rotor go bad as quickly as it did(3 months) and Centric's warranty is only for 3 months(90days).
I have used C-Tec rotors with good success and the Centric Premium w/E-Coating with the same success, except ONE(mentioned).
For whatever reason, this ONE rotor developed a pulsation very quickly and I had to replace it at my own cost. Believe it or not, I replaced it with an AAP WearEver Rotor and it's been great!