I cannot answer your reliability question from a personal standpoint as of yet because the upcoming season will be my first in using the Piazzetta. I have the Sveva which I had installed about a month ago. Initially when I hooked it up the stove didn't respond. After talking to the dealer in NJ where I purchased it, it was suggested that during shipping one of the control board jumpers may have gotten loose. I removed and reset each jumper and got the stove to work that same day.
My stove has only been used once so far and that was on the day of the install to perform a smoke test and also burn off the overspray. What I can tell you through the research I've done in Europe is that Piazzetta is considered a very reliable, efficient, and quiet brand. The pellet forum users over their have a high regard for it. That being said the manufacturer had to tweak the line to accommodate US standards. I can also say that I am confident enough in the stove's reliability and self diagnostics that I chose to have one installed in my home knowing full well that there are no dealers in my state. There are diagnostic codes that the stove will illuminate, and that, in concert with owners manual gives the owner or repair person a list of possible solutions.
NM is a state that is slow to change. Travis Industries, Harmans, and Quads rule here. Contemporary styled stoves are not valued so those homeowners of a similar ilk to myself end up going out of state for solutions. The installers were very impressed with the stove. For someone to make that kind of statement about a piece of equipment is not enough to sway me so I asked why, specifically.
They talked about the ease of access to the innards. 2 screws and the majolica ceramic removed and you have access to all of the mech (mechanisms). The layout is very thoughtful in that all of the potential replacement parts including the control board are easily accessible with plenty of room to remove and install those parts. The auger motor is hefty and solid yet operates quiet. The same can be said about the exhaust blower. The tangential room blower is whisper quiet. When I started the initialization process we didn't think either of the blowers had come on. A side panel had to be removed so that the installers could visually verify that both blowers had come on. The igniter is also easily reached and replaced.
The control panel has numerous functions that are considered standard in Europe one of which is the 7 day, week, weekend programmable thermostat. There's also eco mode which sets a bandwidth for temperature operation that will put the stove in a standby mode once the set temp is reached. If the stove exceeds the bandwidth, it then self cleans and shuts itself off. When the temp decreases to another set-point it will re-initialize and turn itself back on.