I recently bought a set of carbon clinchers (60mm) from a friend. I've had Campagnolo Khamsin and Campagnolo Scirroco before them and they are absolutely awesome to ride.
They don't do anything better. However, they sound immense, look immense, roll for days and when you brake, the sound is like nothing else.
I've read quite a bit about the braking surface. As for rain, they're marginally worse than alloy rims. In the dry, they're just loud. They brake fine.
They also don't wear as people think. Then general consensus is that the wheel will fail before the braking surface does.