Usually, the safest and fastest DNS to use is the one your ISP provides you with. It is faster because the servers are typically physically closer, meaning there will be less latency.
However, since Google DNS servers validate DNSSEC (which is DoS attack prevention) and ISP DNS servers may not (some do, but most don’t) and Google DNS also has more in-cache, its
DNS Server might actually be faster to answer.
Google also has load balancing to improve the cache hit rate. Google IP addresses are 8.8.8.8 and 8.8.4.4, so it’s actually easy to remember (it’s a small plus, but a plus nevertheless).
While Google might be fast, I personally think it lacks privacy since it collects your data. Google wants to make money, you know.
If you’re high on DNS safety, you might also want to check DNS Watch (IP addresses are 84.200.69.80 and 84.200.70.40). It’s completely free and offers:
1: DNS neutrality (no DNS request censorship)
2: Privacy Protection (no DNS query logs)
3: No ad networks or anyone looking into your online habits
4: No DNS hijacking (a common problem with ISPs is that you might end up on a sponsored search page when the website you wanted to visit did not return a response. These pages collect everything you enter on them, which is not great for privacy)