I use GoDaddy. And that's only because I couldn't think of anyone better. It seems like the domain registration space is filled with shady characters. GoDaddy's interface is clunky and confusing and every time I go there I wish someone would just take a giant digital red pen and cross off everything that's not needed and it would magically go away leaving a clean interface. But it doesn't happen.
So, once you get used to how it works, you can get done what you need to get done. I'm pretty clueless when it comes to domain names, but whenever I've been going through tutorials on websites, the settings I need to change have been there in GoDaddy, so that's a plus. At least they're not missing anything I need through all that clutter.