I guess I’m a contrarian. My 2010 panel is very much ‘mix and match’. A pair of GRT Hx efis units, plus a grt EIS for engine data; a Garmin (nee Apollo) SL30 nav-com, a Garmin 420W gps-com, Dynon D6 back up mini EFIS (with internal battery); Trig TT22 mode S-ES transponder and ADSB-out; Trio Pro autopilot. Everything works well together. Autopilot can ‘stand alone’ but I always control it with the EFIS screen, which is easy and intuitive. The negative: GRT stuff is very good electronically, but it is a small company of a few engineers, and it is important that you can read ‘engineering documentation’. Not a lot of hand-holding (although questions are answered promptly, usually one business day). But it’s not for everyone. But personally, I - just like 99% of the forum members - think I made the right choices for me.