I am very satisfied with these rotors. They have proven to be of very high quality from the moment I installed them. It had a very good protective coating which I think will prove to be a very good rust preventative. For the price they look very good, are of high quality and offer excellent protection. I had no issues with excessive knocking after installation, and while slotted rotors are known to be slightly noisier than regular or blank rotors, they didn't prove overly noisy. In fact, I'm not sure if the noise I'm hearing is already due to my aging and tire wear. I love the look of these rotors and hope they perform as well as they look and last.