Here is a list of ISP and ease of use
AT&T – works depending on the router used.
Comcast / Xfinity – works if you don’t use their equipment. If you “rent” their equipment they do not allow you to change their DNS settings. They state “it’s hard coded into the gateway to prevent DNS Hijacks and similar attacks.”
MetroNet – works depending on the router used.
Charter / Spectrum – works depending on the router used.