They are hands down the BEST registrar out there for safety of your domains.
Also, if you do business in bulk levels, they'll offer you wholesale pricing. They are one of the largest portfolio owners in the world and built the system to protect and manage their domains, then opened it up to other people after the fact.
They also do more upgrades to the interface than any registrar out there, they're constantly making improvements, taking customer suggestions, etc and continuously have the most cutting edge interface and management tools.