Cycle Sportives

Riding across cobbles is probably a pretty awful idea on any bike. My question is more, does riding cobbles fixed cause significantly more discomfort than riding them geared?

The best way to ride cobbles is to power over them in the big ring so not being able to coast, to me at least, isn't a disadvantage. Saying that, I'd not ride it again, unless someone was buying me a LOT of beer at the end.