Price ($1.xx .coms occasionally) pulls you in, inertia keeps you there. If all you do is use them as a registrar, you'll probably never have a problem, so no reason to reconsider. Plus, it's the biggest registrar, trust in numbers.
Since then I haven't really had a compelling reason to leave, though earlier this year I decided to--as my domains expire--move to name.com. Of course as of today I initiated the transfer processes on the remaining 12 domains.
It's a win-win for me.
https://www.google.com/search?btnG=1&pws=0&q=godaddy...
http://css-tricks.com/15377-this-sites-domain-is-stolen/
etc.