I don't know, real world data maybe? Your one, or 2, or even 10 experiences are very insignificant statistically speaking. And of course it's not a rare story, people who talk online about a product are most usually people with a bad experience, complaining about it, it kinda introduces a bias that you have to ignore. So you go for things like failure rates, which you can find online.

By the way, it's almost never actually a fault from AMD or Nvidia, but the actual manufacturer of the card.

Edit: Not that I care about Internet points, but downvoting without a rebuttal is... Not very convincing