Hassle free shots with very stable brew head temperature.  No temperature surfing.  No waiting for steam and very powerful steamer.  Works off a $10 wall timer.  Easy to plumb into water line.  Drip tray easy to dump and clean.

Needs to be plumbed in.  PITA to fill the water tank while the machine is under a kitchen cabinet.

The Duetto is simply a wonderful machine.  I have owned it for over 6 months and use it every morning.  It's plumbed into a water filter I purchased along with the machine and plugged into a 120V wall timer I purchased for $10 at target.   The 120V option doesn't seem to impact the operation at all and using the timer to warm the machine up 30 minutes before I get up in the morning makes pulling doubles and steaming milk super easy and fast.   Grinding the beans feels like the slowest part of the process.  

The brew head temperature is extremely stable and easy to adjust.   Steaming milk while pulling shots has no noticeable effects on the brew temperature and I have yet to run out of steam even when making several back-to-back milk drinks.   The steamer is extremely powerful and has a learning curve to produce good results.   What I've found is keeping the tip in the center of the pitcher and a bit deeper works great.  You also don't want to stretch the milk as much, i.e. let the steamer do the work.

One concern I did have with the double boiler design is the possibility of "stale" water in the boilers.  While researching the DB designs I came across some references to the "stale" water issue and found "experts" arguing both sides.  I don't know if the filter I'm using eliminates the issue or if it's just not real to begin with but either way it simply isn't an issue with my setup.

I do think the Duetto really needs to be plumbed.  Water tank access is pretty much zero if the unit is under a kitchen cabinet and having to pull the machine out to remove the top tray to access the tank seems to defeat the hassle free nature of the DB PID controlled design.  

With the amount of hassle free use I get out of my duetto, I've never once regretted the price of the unit.  It is such a pleasure to use, I find myself in the rare position of being completely content with the machine.   This is not the case with other of my interests where I tend to continually have the desire to upgrade to something different and new.

I purchased the Duetto from Chris' Coffee and found the experience a model of customer service.   Before the sale Chris literally answered several email questions from his smart phone in the middle of the night.  His no nonsense manner is also very reassuring.  During the sale I dealt with Scott and he handled the order and shipping details without issue.  The unit shipped coast to coast and arrived in perfect condition.   The setup was a snap.  I also ordered a duel stage water filter from Chris' which came with all the parts necessary to plumb the machine into my kitchen sink water line.  The install process was easier than helping my son build his Christmas Lego kits.   I had an issue with my water pressure and Chris' was able to identify the problem and get me a regulator that fixed the problem.