There ares some. Their reaction to events, their ownership structure change, support culture change etc etc. There isn't a perfect way to find that out, but there are indications.
Most of us don’t interact with our registrars often enough to notice changes in support culture, and who has time to be constantly checking for changes in their ownership, if that information is even available? If you’re spending that much energy on your registrar and your work isn’t as a domain trader, something’s wrong.