Prefer AFS
What I like about the AFS is you are only one button away from everything. A row of buttons along the bottom and side with 3 knobs. Easy and intuitive. I’ve used G3X the last 2 yrs because that’s what my current plane came with and customer service excellent. The 6600 has a better processor than the 5600. I believe the 5600, Dynon HDX, G3X, GRT HX have nearly the same processor.
Correction: I think something got deleted or left out somehow. I meant the AFS customer service is excellent. Everyone else is pretty good for tech support but AFS has always been excellent. I installed the 5600 in my 6A and used it nearly 4 yrs until I sold my plane