Be users tend to use OpenDNS as Be's DNS isn't much use. I found various issues with OpenDNS - one of which was routing any of the BBC sites to Telehouse New York (OpenDNS are yanks). This meant you couldn't view most of the videos etc on the BBC.
The main thing to remember is that OpenDNS servers are physically further away from you than your ISPs DNS servers so if there's any problems between your ISP and them then you may end up with worse performance.
I generally recommend installing Treewalk (
www.ntcanuck.com) - it does what it says and it does it "out of the box". ie any user configuration is minimal and well-documented. It is a better (IMHO) solution than messing about with OpenDNS.
As an aside, the OpenDNS people don't seem anywhere near as interested in fixing problems as they once were. That might just be my perspective though.
