Antares, are we disagreeing?
Please see my opinion on backup instruments on a parallel thread:
http://mooneyspace.com/topic/2806-turn-coordinator-or-second-attitude-indicator/page-3
I have two certified attitude indicators, with different kinds of power sources. For me xavion is a third level backup if that is what it is. But rather I am describing it as synthetic vision for situational awareness. That is different from a primary attitude device. Dynon is not a synthetic vision device. It is an attitude device. But there is overlap in function.
But to your main point, let me say I have a great deal of software engineering experience from many consulting jobs over the years. This is not a huge job like building a windows operating system that requires dozens or hundreds of software engineers. A job that can be done by one person is sometimes done worse by many people. This is my experience in the realm of software engineering.
But not to say that Dynon is going to be more stable because it comes from a company. I don't know much about that company, but I can say that I have had my garmin 396 freeze. I have heard from my hangar neighbor that his aspen has had a software freeze. I have heard tail of Garmin G1000 software errors causing big red x's over critical "instrument" displays. Even big faceless companies with lots of software engineers make big errors.
Actually, I was really surprised at first to learn how sometimes even big companies have teams of software engineers but critical components are worked by one guy - when I was a grad student as an intern at the phone company, US West, I ended up writing a very large piece of code used in operations at the phone company. It replaced a piece of code that was legacy and had been modified and modified for like a decade and no one really knew what it did. Several of us were supposed to do the job but we weren't very organized on how to distribute the job and so I ended up doing the full thing. In other consulting jobs, I have learned this happens a lot.
I don't take the fyi about accelerometrs and built in gps to the ipad as a warning not to use their product and to go by dynon because it is better and more stable and more accurate. Far from it. I take the warning as honest, and a warning to carefully choose the sensors depending on what is the mission it is intended to satisfy. For situational awareness (svt view) I am happy with built in accelerometers and external gps. If I did not have redundant mechanical certified attitude indicators, I would a) get a second certified attitude indicator, but at least get a iLevil. That said, I am sure Dynon is a fine instrument. But I am more confident in the stability of the iPhone for now - on principle - and I am quite convinced it is up to the computational task, easily, but I say that fully admitting I have never touched a Dynon, but just my experience with garmin.