I've had the DD-15 for around a week now and have only just started to fully explore the flexibilty it offers. Absolutely stunning performance so far though and I'm sure it'll become even more of a revelation once I've had time to really sit down and play with the set-up. There's quite a few DD owners and discussion about them on this thread:
http://www.avtalk.co.uk/forum/index.php?t=msg&th=3030&start=0&rid=0&SQ=0
http://www.avtalk.co.uk/forum/index.php?t=msg&th=3030&start=0&rid=0&SQ=0