@M Code gave us some industrial inside info on repair records of AVRs. So this is based on actual numbers of units being repaired. But I don't know the exact/specific info. IOW, I think this is based on total numbers of AVRs being repaired for recent years.
It doesn't look at specific model numbers (like high-end models vs low-end or models made in Japan vs Vietnam, etc.).
From what M Code posted, I got 2 things:
1. Yamaha has the #1 Reliability overall.
2. Yamaha has the #1 HDMI-Compatibility overall (of course, HDMI-compatibility from Sony TV + Sony AVR + Sony XBOX would be difficult to beat).