A lot of people have asked which brand of avionics I was going to go with for my RV-10. And they are always shocked when I tell them I'm not going with Garmin.
For some reason, Garmin is always the assumed / foregone conclusion. I think that's mostly due to them probably being the best solution for an IFR setup.. but there is one thing that will win me over / or make me leave, every time.
Customer Service. And frankly, I haven't had good experiences with Garmin. At all.
My bad experience started with a Garmin GPS system I have on my motorcycle which bricked itself the very first time I updated it using their software. I had to go back and forth with them for weeks to get them to replace it, with the tech support wonk telling me it was my fault that the device bricked. But he was more than happy to sell me a new one!
There system could see that this was the first it had been updated, and could see that the update had failed apparently. (I guess the updater phones home while updating?) But some how that's my fault.
As you might imagine that put a rather sour taste in my mouth, but it wasn't what swore me off of them.
No that came when I visited their booth at Oshkosh a few years ago.
I was making the rounds to all the avionics vendors and the Garmin folks couldn't give a crap about customers walking and asking questions. They didn't have time for anyone, didn't bother to care about us in any way, and were down right rude when questions came up. etc..
That did it for me. You don't want my business, then you wont have it.