The La Spaziale Vivaldi II is a single-group dual-boiler machine ideal for an extreme espresso enthusiast and well-suited for a small commercial operation (e.g., sandwich shop that produces the occasional espresso). Its strength is its rock solid temp and pressure control, even when steam is also being used.
I purchased this machine after my 14-year-old PID'ed Gaggia Classic developed a leak and started getting flaky. (The price paid includes the 7-day programmable timer.) My primary goal was excellent shots, with steaming and hot water being less important. However, now that I've got this dual boiler machine I find that I'm steaming more, and also making a lot of americanos; the hot water outlet is also convenient for tea. The Vivaldi has built-in adjustable PID control and a front-panel display that tracks the espresso water temperature; the temp stays stable as a shot is being pulled and the heater is powerful enough to produce shots in rapid succession. The result is that I can get extremely consistent shots whether it's the first shot of the morning or the fourth in a row when serving guests. I can save my tweaking for the grind (I use a Mazzer Mini so that too is very consistent and finely adjustable). With a bit of experimentation I've been able to fine-tune the temp to the particular blend of beans I use.
I don't think I've pulled a bad shot since the second day of using the Vivaldi, and at this point 90% of my shots are better than 95% of the shots that I get at commercial espresso establishments here in Seattle - that's a pretty hefty claim, given that I pick my cafes with care, but it's true. The only limiting factor is the freshness of the coffee - I don't go through coffee as quickly as a cafe can. With the Gaggia, an excellent machine in its own right especially when PID'ed, I never felt that I was getting the subtlest flavor notes fully developed. With the Vivaldi it's all there, consistently. So, for instance, I've switched from using Caffe Vivace's "Vita" blend to their "Dolce"; with the Gaggia, the funkiness of the Vita was desirable and the subtle toffee and citrus of the Dolce never really came through unless I had it at the Vivace shop. With the Vivaldi, I can get the fine notes of the Dolce at home, reliably.
So, the shots are great. The steaming is still not great. I rarely used to steam; now that I've got a double boiler machine I've been trying to learn, but I still don't feel I've gotten great microfoam with the Vivaldi. That's probably my own fault, just lack of skill and experience. However, I did just find out that Chris has a new steam tip with smaller holes; so perhaps that will make a difference. In any event, I can't really rate the Vivaldi on steaming because of my own limitations. I will say that there seems to be plenty of steam pressure and the wand and steam knob are easy to use.
The front, top, and back panels of the machine easily remove to get access to the internals. The innards are laid out well and seem easy to work on; the quality of the plumbing work is excellent. Hooking up the water line was trivially easy. I have had no problems with leaks or rattles; the rotary water pump is quiet and provides good consistent pressure. Chris' helpfully provides an extra set of showerhead filters and a hex wrench, so it's easy to swap out the filters, backflush, and put the dirty filters to soak in cleaner: back up and running in about two minutes.
There are a few negatives. On arrival, the pressure meter had gotten pushed around and wasn't fitting into the hole in the front panel that it's supposed to be framed by. Even with some bending and tweaking it still doesn't quite line up square, and each time I take the front panel off it seems to need to be pushed around again to get it to pop back in. Also on arrival, the timer was defective (the clock wouldn't keep the correct time of day); Chris' replaced this immediately and the replacement has been fine. The programming interface on the timer is just absurdly bad, you need to step through dozens of button clicks to make minor changes and if you do anything wrong you have to start all over again. There's a helpful cheat-sheet available on a Vivaldi discussion forum online; Google for it.
Perhaps most annoyingly, the fan that turns on whenever the steam boiler is heating made a loud whining noise, noticeable enough to disrupt quiet conversation a room away. Chris' sent me a replacement fan, but it was just as loud. I was eventually able to fix the problem by removing the existing fan and installing a slightly larger fan (with a current-limiting resistor to reduce the speed and CFM) on spacers underneath the bottom plate; this worked very well, but might be beyond the capability of many purchasers. I hear that Chris' have since made some additional modifications so hopefully new units are quieter. As an electrical engineer I happen to believe that the fan would be entirely unnecessary with a minor redesign of the electronics, so that's a little frustrating for me, but oh well.
Bottom line is that this is a very solidly built, extremely high quality machine that reliably produces excellent espresso. At this point I honestly do not feel that there is any machine in the world that would do a better job, for any amount of money; I'm regularly getting espresso that's as good as any that I've ever had, from award-winning baristas in Seattle and around the world. My only limitation at this point, for straight shots, is the beans. For milk drinks the jury's still out, because of my lack of steaming skill.