This is being described as a privacy-focused tool, even though Cloudflare is getting access to gobs of data and traffic and could be doing stuff with that data. But if it's fast and works well, and your ISP's DNS servers don't work so well, it might be something to try.
There are actually a number of other DNS services like this out there.
Google Public DNS is perhaps the most well known one. (It's the one I use most often.) To use their service, you set your DNS server settings to use 184.108.40.206 and 220.127.116.11.
There's also OpenDNS and Quad9 that are intended to help block bad stuff.
And you can find even more services like that here. With all these options, does a savvy geek even need to run their own DNS server nowadays?
Though, I'm not sure it's safe to try to query DNSBLs (anti-spam blacklists) through these DNS services. It's entirely possible that some DNSBLs block them as they may appear to be overwhelmingly large sources of traffic. (Or possibly a DNSBL might like this if the DNS service effectively acts as a cache for them; but I don't have any data on this.)