I have been with Gandi for years. They are a bit more expensive than some other other registrars, but offer good service, and donate proceeds to non-profit projects:
I recently moved to name.com. I absolutely love their minimalistic interface, and I like supporting local business (Denver)...
So far no issues what so ever other than with GoDaddy and moving domains over because of issues with whois, but once there everything is fast, and simple. Unlike GoDaddy's interface.
I'm not sure if they're still doing it, but the thing that drove me away was their spammy DNS.
Example: I had valid DNS records for mydomain.com and www.mydomain.com but they were forwarding ANYTHING.mydomain.com to one of their ad-ridden pages.
I can kind of see an argument for having that when a domain has just been purchased and there is no valid content yet. But doing that to an established site makes ME look like a spammer.
tl;dr - if you're using name.com's DNS, you might want to see if they're hosting spam pages on whatever.yourdomain.com
I do my own DNS hosting, I've never used a registrars DNS services, I've never found them to be reliable enough, nor do they meet my needs in terms of being able to update records quickly or in programmatic way (such as hosting my own DynDNS like service, keeping a record updated for my home IP address).
http://en.gandi.net/supports/