How accurate are garmin avionics?

After re-reading the original post I realized the following is probably irrelevant to the OPs question. And I like to complain about those who go off on a tangent.... However, since it's done, someone might get something out of it:

It's interesting you ask this question. On my homebuilt I originally installed an old style attitude indictor. I trusted that device after a couple of inadvertent IMC situations. Then it went TU and I went with a G5 (at half the cost of a certificated one which still makes no sense to me...).

I did not really trust the G5 for a long time. Not sure why, but I felt the need to frequently cross check data from my remaining steam gauges (VFR). I think part of my brain was struggling with the idea that there was so much data on a tiny screen, that something could be off. I actually regretted installing it for a long time because I didn't trust it, though I had no real basis for this.

After a lot of flights and some encounters with bad weather I've changed completely. The fact that in low vis or turbulent situations I can get everything I need to control the plane from that one tiny gauge. Again, I'm talking VFR situations here, not IFR.

Two weeks ago I got into some extreme turbulence (for my LS) and just being able to focus on that one gauge was a huge benefit.

Not exactly sure how "accurate" they are, but they are clearly accurate enough for me. After using my G5 for a while I wouldn't want to fly without one.