Skytrax seems to be the industry standard.

Edit: nevermind you said SAFETY ratings

Didn't he actually fly it himself as part of the process?

Yes, in the video I linked he speaks about it, this is the full quote

> After that, I flew the aircraft for about two hours to evaluate its handling qualities and the functionality of the flight control system. Now, based on all the activities that we've undertaken during the past 20 months, and my personal experience flying the aircraft, I can tell you now that I am 100 percent comfortable with my family flying on it

So, he done 2 hours of what pilots will do for more hours, every single day they work. He also haven't trusted other pilots, let's say from Ethiopian Airlines, with his family.