I learned one during grad school which is meant to serve the school network but accepts requests from anywhere. I've just kept using that.

is there anything wrong/dubious with openDNS?

yes. see tptacek's comment.

You can easily configure OpenDNS to work exactly like a normal resolver.

People always seem to forget this point.

I didn't forget that I can login to OpenDNS and fix my settings every time my IP changes, I just think it's ridiculous.