Which ISPs are so bad that you want to use external services, which are further in distance than your ISP, for speed? When I test with my ISP, they beat all of these services (both IPv4 and IPv6). They're simply closer to me in terms of hops.
My router is another story though. The Fritzbox (>200eur router) adds 6ms of latency, and that's what is advertised over DHCP. (Might still be fine, since cached queries are faster than the ping time to the ISP.) Note that my tests were all with uncached queries (random subdomains of a domain), so it always had to go out and ask an external server (though it could cache the NS record for the domain).
My router is another story though. The Fritzbox (>200eur router) adds 6ms of latency, and that's what is advertised over DHCP. (Might still be fine, since cached queries are faster than the ping time to the ISP.) Note that my tests were all with uncached queries (random subdomains of a domain), so it always had to go out and ask an external server (though it could cache the NS record for the domain).