It's much better when there's no traffic. When there's traffic, it often doesn't stop for you when it exits the roundabout (even if it technically should) because everyone is busy going around the circle as fast as possible (and driving in a circle means they might not have been looking at where you crossed). Sometimes they move the pedestrian crossings way back to give people more of a chance to stop, but that still requires drivers to stop when they don't feel forced to.