As a non-web-dev, I'm still looking for a reason to not use Safari on my macbook. Perhaps I'm too dumb to see the difference, but I've never found chrome/firefox to be better than safari.
As an exercise in trying to install the minimum amount of software on my Machine, I'm using Safari as my default browser. However, there are cases I have found where a website simply doesn't work with Safari but has been developed and tested against Chrome.