I used to use OpenDNS several years ago (before it was bought by Cisco), but also faced some issues not directly related to the DNS service and stability. OpenDNS allowed people to create accounts and specific blacklists/whitelists. That, when combined with the OpenDNS app (same user account) that would run on the users' computers, would tell OpenDNS which sites to block for which source IP address (the user's) even for those with dynamic IP addresses from their ISP. Being on a connection with a dynamic IP address, once in a while I'd get the IP address of someone else who had the OpenDNS filtering setup and hadn't run the OpenDNS app or it somehow failed to report back (or the time between the periodic pings from the app with the IP address update). When I used OpenDNS servers during those times, I would get blocked out of sites and get weird custom messages that those users had setup. The only solution was to create an account myself on OpenDNS, run the OpenDNS app on all my systems, and trigger an IP address update back to OpenDNS from the app if at all something didn't work.
I'm guessing the same filtering support still exists, called Home Internet Security. [1]
One tool I have used in the past to benchmark DNS servers and choose is namebench. [2] It seems like the last releases were in 2010, but it worked for me even a few years ago (haven't checked after that).
[1]: https://www.opendns.com/home-internet-security/
[2]: https://code.google.com/archive/p/namebench/
