Love it! Didn't know if it would be that much more of an improvement over my older Alex, but wow it's a keeper!
Positive Product Points
Only a couple weeks in to owning the Duetto, but I really love it. Owned a Izzo Alex for a couple years now and made the jump. Played a bit on a Marzocco GS/3 before buying this, but in all honesty I don't think another 5 grand gets you much more of a machine. Love the PID, and how easy it is to adjust shot temperature. Having a bunch of fun! E61 is still a great head. Love the side panels, but...
Negative Product Points
...Side panels add a bit of girth. Takes up more space than my old machine. Rattles a bit. Narrowed down the problem to the drip tray. Had some RTV silicone gasket maker, removed the tray, and added about 10 uniform dabs around the edge of the ledge the tray rests on and waited for it to cure before replacing the tray. Worked like a charm, no more rattle.
Still have lots of experimenting to do, but loving the decision to upgrade. The dual boiler and PID are rock solid. Was easy to plumb into my fridge water line with about $5 in parts from Lowe's.
Steam is abundant. Very comparable to the GS/3 in my limited time on one. Great frother, making great micro-foam. Only had one evening with friends over at this point, but it kept up quite nicely to about 15 milk based drinks in short order...never seemed to need a recovery time.
Probably not a negative or positive, but wonder how stale the steam boiler can become?
Ordered my Aeropress from Venia Coffee on a whim (hadn't heard of them before then) but had a great experience so I bought the Duetto from them as well (much closer than shipping from Chris where I bought my first Izzo). They didn't have any free-bies on their website, but I gave them a call and got a new C-Ripple Candy Red Reg-Barber tamper and a group brush thrown in. Best tamper I have ever touched.