I have never once had a problem with OpenDNS in the year or so I have been using them. Their system status can be found here
OpenDNS > System (also available at http://208.69.38.170/). Any problems with a data center cause traffic to be re-routed to the nearest center. I would say that any system that handles 19+ billion queries a day would have to be pretty reliable
For BIND you just need to change the forwarders directive.