In reply to Luke_G:
For mellow long sport, I'm sure the Nano is more than good enough.
How ever, on a desperate redpoint project, or hangdoggin' session, you'll prolly want the biggest and easiest to clip biners, with thick draws (so easier to hangdog and check out the next moves). I've been rather happy with Petzl Spirits, and they seem to be benchmark there days. Sure WC Protons and DMM offerings might be on UK climbers rack.
That said, Ocun and others make almost as good QDs/biners at a lot cheaper price.
My sport draws are old (but still keylock) BD Positrons, which can be had for peanuts. I've swapped about half of the draws to 17 and a few to 25cm Petzl Spirit draws. Seems to work out just fine. Not light though, but then again when compared to a proper rack, a few weighter QDs are still a lot lighter.