This summer I have been climbing with the newest Beal rope, the Diablo. With 9.8 mm it's not extremely light and thin. Nonetheless I experienced this rope as extremely flexible. With 61 g/m it's pretty light compared to other 9.8 mm ropes and even some thinner ones. My previous experience with light, thick ropes is that they are flexible, but also fragile. In most cases I have to cut off the ends after just one or two weeks of climbing outdoors. Therefore I was amazed how good this rope stayed. After two weeks of intensive use in Ceuse it doesn't show any marks of wastage. In my opinion this makes it a perfect rope, with the flexibility and weight of a low 9 mm and with the durability of a thick rope. I could definitely recommend it!
More information: http://bealplanet.com/sport/anglais/corde-diablo98.php