In reply to jon:
I've been using them for about 8 weeks now and in the hand they don't feel really any different from the 8.9 and 9 triple rated ropes I've used before BUT very few belay devices are rated for a single rope that thin so you pretty much have to use the Edelrid Micro Jul with the Corbie if you want to use it as a single.
So, yep, it is very skinny as a single but it doesn't look anymore scary than say a Beal Joker (although I remember being terrified top roping on one of them when I first tried it years ago!).