Coming into the topic a little late, but I've had my domains registered with various registrars for a little over 7 years before hopping to DH for both my DNR and for my webhosting needs.
I have used:
There's no particular reason for me to go anywhere else, really. In my 7 years of owning and managing domains, I have experienced some of the nastiest things that have happened in the DNR business and most of it at the hands of RF.
Once RF went down the can, I got my stuff moved to GoDaddy (I didn't choose this; this happened because of the legal process involved) and after seeing the craptastic way they do control paneling and seeing how they try and sell something at every click and corner, I more than had enough of them.
DH was simple and easy to configure and offered the same valuable options the other registars were offering MINUS the headaches and time wasted.
Especially if you have DH hosting and you like DH hosting (if you don't like it, why are you still here?), there really is almost no reason to NOT choose DH for your .com, .net, and .org domain registration.
The only thing I can think of that would make a registrar like GoDaddy more appealing would be their discount coupons they offer from time to time.
I. HATE! PUSHY. SALESPEOPLE! And I used to be a sales associate once upon a long time ago!
And GoDaddy is THE fatherlode of pushy salespeople and 'salespeople'.
... That, and I get sick and tired of seeing the same damned 'trying to make GoDaddy sexy' advertisements EVERY. SINGLE. TIME I log into the site.
I'm looking for reliable domain name management, HELLO? Anybody home? I need a solid control panel and I need it and all the related domain management features to work!
If I want my girls, then I know of better places to find my own eyecandy, thanks.
... No offense to Danica meant, of course.