For the past several months, we have used the exceedingly reliable DNS replication service,
BuddyNS. Their service is free for medium-weight websites, and is surprisingly powerful and useful.
We personally monitor all services HackThisSite uses (including our record availability on
BuddyNS's nameservers), and not once have we ever bounced a proper DNS request for our systems. Furthermore, their management systems are custom developed in-house and are very useful. This impressive functionality and high-availability is why we have entered into a partnership with
BuddyNS.
Our domains actively utilize their systems every day, a constant successful test of their reputation. We encourage those concerned with uptime to give
BuddyNS a shot.
(Full Disclosure: This is not a paid sponsorship. This is a partnership agreement made with
BuddyNS, and is purely motivated by HackThisSite's appreciation of their higher-than-usual support of our systems.)