I've had my Quattro for a year now, and I've been very happy with it. With it's square configuration, it looks a bit different from the other gauges, and the avionics guy had to cut the false panel to match, but it looks OK. It took a little tweaking at first, which meant returning to the avionics shop, because the pitch and bank were a little off, and they're not pilot-adjustable. The shop had adjusted them to show straight and level on their ramp, but there was a very slight tilt on bank and the pitch was quite a bit off in flight, actually showing a climb. That meant that if the Quattro showed level pitch, the airplane was actually pitched down a couple of degrees. So I took some pictures with my phone, and they adjusted things accordingly.
Here's how it looks:

Quattro has come out with a new software update, which I'll consider when it's time to do the pitot/static check next January. The unit has to be pulled and sent to the factory for the update, because they then recalibrate and recertify it, which of course means disconnecting it from the pitot and static lines. Sandia is doing the update for free, but the avionics people would then charge for the R&R and the pitot/static cert. The update includes several things that might be helpful:
1. An instantaneous vertical speed window (instead of the several second lag of a typical VSI);
2. An altitude bug, i.e., an adjustable window as a reminder to the pilot of the altitude to maintain; and
3. Most useful, a choice of the current default shut-down, which reverts the Kollsman window to 29.92; or a shut-down which retains the currently set altimeter setting; or a shut-down which retains the current altitude. That last would be nice for having the current altimeter setting upon take off from a strip where the altimeter setting is otherwise unknown.
All in all, I'm quite pleased with the Quattro. I like that its lighting is both automatic with a light sensor and manual, with the knob. Its presentation is easy to read, both night and day. And its altitude is right on, better than the stock altimeter, which is within legal tolerances but a bit off of the actual altitude. However, since they're slightly different, I set the stock altimeter's altitude to match the Quattro's, and then on approaches, I still watch the stock altimeter for the DH/DA or MDA, because its analog presentation is what I've flown all my life.
Cary