Ceramics have few disadvantages IMHO:

-slower response on brake pedal on wet road or low ambiente temperature

-more fragile structure of Ceramic discs-prone to damage(my friend broke Ceramic disc on his 997 CS from small rock that was on the road)

-price


Regarding superior performance... Around 85% of all 997 Turbos are used as daily commuters in city so, good question is what is advantage of Ceramic Brakes in wet road city commuting? None? I think so...