Well made. Feels like a Sherman Tank that has been chromed.
Workmanship is unparalleled. Wire ties are used throughout. It is a little thing but it speaks to the overall quality.
Great crema from the first shot
Extremely easy to use. PID takes out all of the guess work

Can't think of any.

I had an Olympia and La Pavoni Pro for many years. The Duetto II makes a better shot, hands down, than either of them.
As with any machine there is a learning curve on steaming milk. But after three weeks my attempts at "latte art" was good enough to take a pic of it and show to my friends.
Chris' provides a great user manual that is down-loadable from their web site.
At first I was concerned about buying this type of machine (and price) over the phone. Turned out not to be a problem at all. Refer below to "Buying Experience".

Best part of the purchase. I worked with Scott from Chris' Coffee Service. He is extremely knowledgeable and was more than willing to answer all my questions during our many phone conversations. He knows all the machines and could describe their pros cons in a very objective manner. His support has been just as good after the sale as it was before I made the purchase.
Check them out:  http://www.chriscoffee.com/