Most pads nowadays are metallic. I don't know specifically about the Prius. Since most Priuses don't need to have a brake job done until well after 100,000 miles, it's not something that most owners have much experience with!
This has been discussed on PriusChat before, with no clear cut resolution. The composition of the Gen II brake pads is one of the very few questions about the Gen II that have not been conclusively resolved here on PriusChat. I remember one discussion where one PriusChatter said that an online parts store described the "Prius OE" pads as ceramic. I went to that website and found that yes, it did describe a set of "Prius OE" pads as being ceramic, but it also described another set of Prius OE pads as being semi-metallic. Personally, I doubt that the pads are ceramic. But if I ever need my pads replaced, I'm going with performance pads (could be ceramic or other), like one of these from Hawk: Brakes Products for Toyota Prius 2007
I am in fact considering the Hawk replacement too, even though my car only has 4k miles on it. (was thinking of getting it done at the 5k oil change...) I'm not particularly impressed with the braking on the Prius, and in emergency braking situations it'll mostly be friction braking doing most of the work...
The braking of the Gen II Standard Prius is subpar. When I checked last year, the 60-0 mph dry and wet braking distances of the Standard Prius ranked only in the 11th percentile of the over 100 current model sedans tested by Consumer Reports. The 60-0 mph braking distances of the Touring Edition Prius are much shorter -- 10 feet shorter dry, 12 feet shorter wet. I think this is attributable to the wider and better OEM tires on the Touring Edition. I think that you too can achieve the Touring Edition's better braking distances by installing wider (195/60R15) and better tires.
The OEM pads can lock the wheels, so better pads aren't going to help your stopping distance. Advanced pads are mostly an advantage when dealing with fade, which occurs with prolonged braking. Prolonged braking isn't normally an issue with the Prius due to regenerative braking and B mode engine braking. Tires are another story. All braking force couples to the ground through the tires. The OEM tires on the Gen II Prius are not very good. Better tires will help a lot. Tom
