OK Steve
We're still arguing about it here but I think the upshot is, you can see gains if your ISP was previously routing you over its partner networks in order to save money, but that route is slower than the optimum one given by OpenDNS. However this isn't my area.
You can have a laugh with this by downloading the excellent free traceroute tool Webhopper, and seeing the countries your traffic gets bounced around:
www.proletary.com
To get nextdoor you are sometimes routed halfway round the world - twice. I guess this would explain why ping time is so bad sometimes. This tool is good because you get to see the countries immediately, a command line traceroute can't do that.
Choose a site or IP and watch your traffic go back and forth between countries that are nowhere near the place you want to go
Why can't it just go straight there like when I get on a plane to go there??