First of all you want a dns server close to you to get the best speed, the fastest DNS server will be a local or semi local one. Secondarily as a principle the speed of the dns server is not that important, what really matters is that it is stable and that it doesn't limit you with stuff like webshield2 etc so that your isp don't block unwanted traffic. Opendns would be an option for you if you have issues but most people would not need it. In most cases you can get around blocks by just editing your host file in windows