There are a lot of variables on this topic.
I have wavy aftermarket discs up front and my Galfer sintered pads are barely wearing at all, and are hardly scratching the surface of the discs either, it's a perfect scenario.
I've just tried SBS ceramics on the rear and after a couple of weeks of bedding in i'm very impressed by the pinpoint accuracy of braking when used in traffic, they are very responsive and bite well.
I would avoid sintered on the rear, as they are a bit harsh.
If you're interested in the Galfers they are much cheaper from Calsports site on Ebay, rather than their normal website.
I would be bold enough to say that this combination of pads is the best i've ever had in years of biking.
