I believe EBC Greenstuff pads are Kevlar? I have them fitted to my car and they work great from cold. Slightly better when warmed up (I mean a few seconds normal braking), but they're by no means track pads. I used to have Ferodos and I much prefer the EBCs.
I was driving on a dual-carriageway soon after fitting them doing around 90MPH, the brakes hadn't been used for a while so were probably cold. Someone came into my lane doing about 50MPH and I stomped the brakes, locking the wheels and slowing to 50 real fast. I have 215/45 tyres and the road was dry, so I can have no complaints about my braking performance

I'd recommend them to anyone.
Paul.