Ok so here are my thoughts on the different GTN750’s.
The one here in the forum that shows up in the game is cool but limited and does not work well with a touch screen, hopefully that part will change. I’m sure it will gain more functions too. Now if not using Air Manager and or a touch screen this is the way to go.
The other one to purchase is the Garmin Trainer with an MSFS link. It is the full blown GTN750 and functions great on a touch screen. It links with the plane well. When you change radios on it they change in sim. What does not link, if you put a flight plan in on the 750 it does not show in the sim but the autopilot will follow it and the nav indicators are linked but it does not show in the in game GPS map. Not a big deal to me.
The issue I do not like is when you touch it to make changes it of coarse takes focus away from the sim window so you have to remember to click back on that. Would be nice to have a button that put focus back on MSFS that you could bind to your joystick.
I think both have there place depending on how you use the sim. I look forward to the in game version improving and finding better ways to use the other one in Air Manager panels.