avionics consistency and longevity..
In my second RV now, but what I based panel and layout was the vendors ability to stay consistent with design....i.e the holes in the panel!...
Upgrades, hardware & software are a way of life now, good or bad, just reality if you want a glass cockpit. I have gone with Dynon for several reasons, but one of the most important, was their consistency of display and data processing modules, all plug and play, easy to upgrade (other than the pocket book!). There is really little left to the imagination these days with layout, much like the days of the "six-pack", today its two displays, com, nav/com, and audio panel, a few switches to your liking, and put an I-pad or other display to keep the passengers happy. I have so much information sitting in just one 10 x 7 in display I just can't imagine looking for other display technology to make flight safer or bring in more situational awareness to the cockpit. All the warning lights of your choosing (door, alt, etc...) will not change over the lifetime of the airframe most likely, so install and punch holes in the panel.
Maybe I am just too easy or too old, but take me two-steps back and the technology is just awesome and very very safe to fly with. But I fly to get places, have fun, and do it safe. I don't need the best of the best or the newest version in the cockpit to accomplish a safe and fun flight. You need to make some of those choices for yourself and your mission in the aircraft.
Good luck and have fun flying, always!