208.67.222.222 is one of the open DNS IP addresses while 8.8.8.8 is used by Google DNS. Either may be faster than what you are using now which is usually the DNS server operated by your ISP. In some case it can be substantially slower, particularly if you do not live in the US. It all depends on how well your ISP DNS server performs. As this server is probably close than others it will have an edge, but there are many other factors that come into play as well. The only way to tell is to try.
There is a downside to using Open DNS, and possibly Google as well. With most DNS servers when you attempt to go to a website that does not exist the browser will simply show an error message. With Open DNS you will be taken to a site displaying advertising. Downloads may also be slower.