These things have changed quite a bit in the last several years. Now, of the big 4 EFIS companies, the stability of the hardware and the software is seldom a concern, IMHO. I have not flown much behind the G3X, but the other 3 I have flown behind a great deal, and flying an IFR approach on all 3 is quite simple, albeit a little different from one to another. They all have good systems for coupling approaches and for going from heading and altitude control to coupling on the Nav and Glideslope. The external control panels for AFS and Dynon (& I assume for the G3X) can make it that much easier. Hangar flying can be very helpful, but learning the actual procedures for flying an approach can really only be done while flying an approach. It's impossible to simulate the approach and coupling in the hangar without a good simlulator. For example, I didn't realize the AFS would level you off at the minimums you specify until I flew an actual approach.
When choosing among the big 4, especially if moving to glass for the first time, your impression of the system from websites, sample panels, trade show displays and reading on here can drive the decision without much touching and feeling, although the touching and feeling can help. Talking to someone who has one system in EIS plane and is only familiar with that system, is not going to help get an unbiased decision. There are few people who have flown all systems and fewer still who can provide an opportunity to sit in a plane and push buttons on multiple systems. Finally, of the big 4, any decision you make will be a good decision, IMHO, and you will be very happy with it. Some systems ar more scalable than others, but they are all good systems. All of the systems have quirks that can be annoying, but they are not show-stoppers.
The OP came to my hangar on Friday and looked at both AFS and Dynon. After looking at the AFS, he was definitely leaning that way. Once he spent a little time looking at the Dynon, he chose to go that direction. I'm not sure what the driving factor was in his decision, and when I asked him, he wasn't sure either. I guess he just somehow felt like Dynon was the way to go, for him.
YMMV, but you won't be disappointed with any of the big 4, and you may even be surprised by MGL as well, if you decide to go that route.