If you’re up for some light reading: http://www.tummy.com/Community/Articles/famous-dns-server/
If you’re not the “reading type,” here’s the key part of the article: Should I Use 126.96.36.199? Unless you are a Level-3 customer, absolutely not.
Essentially, 188.8.131.52 belongs to Level 3, and they have no obligation to ensure that this service is reliable or accurate. As of late, a number of DNS queries made against 184.108.40.206 have been timing out, which makes it a bad choice to verify DNS name resolution.
220.127.116.11 and 18.104.22.168, please.
To add to this, Allied Telecom (and my independent tests) have noted that 22.214.171.124 is having some major issues today, which is manifesting itself as many of their customers calling them for Internet connectivity issues when the issue actually lies with the DNS provider that the IT Engineer chose to put in the firewall/DNS settings long before 126.96.36.199 started going downhill.