Open DNS has services related to their dns servers, such as phishing protection or parental controls, though you may have to sign up to configure them.
Selecting a server with better response time can speed up browsing
Open DNS now offers an encrypted DNS tool, which keeps anyone from seeing your DNS requests. No matter whose DNS servers you use, your ISP knows every webpage you visit, even if the webpage is SSL, the DNS request is not encrypted even though the connection to the website is SSL encrypted, so they came out with the tool to take care of that vulnerability.
So it can improve browsing speed and security, you may not get both depending on where you are.