We think it's safe. We make this stuff for a living, see the failure rates, and know the issues. Yet, this is our airplane, fully IMC equipped. No dissimilar systems, no steam gauges. We would not say that you should fly in IMC with NO backups, but in my opinion, pretty much any backup is reasonable given the failure rates of a modern EFIS system.
I realize it's not for everyone, but if you are willing to fly IMC with a single engine, a single pilot, a single pitot, single com, etc, yet worried about crazy redundancy in your panel, you may not be focusing on the real and likely failure points.
The advantage of a fully integrated system like this as well is the reduction in workload when everything is working normally. No cross-checking stuff yourself, no setting two barometers, huge screens full of information, no "partial panel" when a screen does go out. You need to balance the use of a system in IFR for the 99.99% of the time it's working well with your capability if it ever does go out. Most accidents are not equipment failures, they are human failures, and anything that reduces that is a huge mark in the win column.
Oh, and we have 3 screens because we can and we use them for testing, not for redundancy. 2 screens are as good as 3 in my book.
--Ian Jordan
Dynon Avionics