I stumbled upon namebench, another tool from Google. Namebench evaluates the performance of public DNS servers, including the current configuration, and Googles own public DNS server. The tool creates a list with the test results, and it turns out that I can gain 185% improvement for DNS queries when switching. Is it worth it? I guess that most of the accesses I do are in the meantime cached. But anyway, thanks to Google for trying to squeeze more speed out of the Internet.