I have driven, been trained on, and serviced both. The single clutch systems are much simpler and very efficient though do not take as well to very hard driving as the dual clutch systems. The dual clutch systems are far more complex, more expensive, and heavier. For that you get increased shift speed, a more smooth feeling shift, and a more robust unit. That said all the AMT transmissions I was trained on cost more than an entire elio, so I'm very interested to see just how much more expensive they will be than the manual. I am also much more interested in considering an automatic as an option if it's an AMT transmission as I feel that it is a more robust/servicable design than a traditional automatic or a CVT and it reduces drive-train loss within the drive line.