Jond,
I have been thinking about this switch for a long time. Through all my reading I have found there to be agreement that the analogue out of the touch is much better than the duet.
I personally use a dac so using the digital out from the duet. There are many opinions on sound quality using a dac and either the duet or touch. Many believe that the touch is better but just marginally while many others believe the difference an immediately noticable upgrade. I have come to believe that the upgrade will be an improvement. That belief combined with higher resolution audio supported by the touch helped sway me that way.
What pushed me over the edge was Logitech dropping the touch. I think they will be hard to find used (already are) and I knew that I would never be content till I tried one.
At the price figured I could sell the duet and pay for the touch if I wanted.
hth
Steve