When I was looking at a mini-EFIS, I looked at MGL Extreme. On the upside, it can control STX 165R. On the downside, needed external GPS antenna and the behind the panel depth was 4 inches -- barely enough against the lap tank. Although it fits a normal round hole, the head is offset up and to the right. What helped me decide against them is their love of membrane buttons.
I eventually decided to buy Sandia EFIS. It's quite expensive, but I liked their software. They may be the only one which can self-align the MEMS just using the gravity. Everyone else requires either a magnetometer or GPS. The manual of GRT's Ultra clearly states that in case of a loss of GPS signal, the attitude information goes away in 100 seconds. Fortunately or unfortunately, I crashed the airplane before I had a chance to actually buy it.