I was always told by colleagues 22.214.171.124 appears to work faster and have to combine that with Google's public DNS. Basically using 126.96.36.199 as primary and 188.8.131.52 as secondary. However, Google only provides 184.108.40.206 and 220.127.116.11, so who provides 18.104.22.168? And if true, why is 22.214.171.124 faster?
Note: These IP addresses are used to dig domains and to determine if local DNS changes has propagated over all over the internet.