This is not to say that using OpenDNS is always perfect — rather that it’s better than hoping that your ISP DNS options never fail on you as they often can.
Now here’s the rub — OpenDNS can in some cases provide problems for certain VPN setups. Short of this, it’s awesome and generally stable. I also love the fact that you can provide content filtering, among other content control functions, through OpenDNS’ control panel.
The above linked article makes the claim to fame that OpenDNS has had zero crashes. This is a fairly solid claim, I believe, based on how steady my experience has been. But this is not to say that I haven’t seen sites like Google drop out of OpenDNS from time to time. It’s happened, but it’s rare.
At the end of the day, OpenDNS is pretty awesome and as a secondary DNS option, it’s something I use frequently.