I created this DNS test. If your are evaluating DNS services, you might also check out a blog post I wrote last month summarizing the results we've collected from the DNS tests: http://blog.cloudharmony.com/2012/08/comparison-and-analysis...
Wow - you're seriously a hero. Thanks so much for building the test and thanks (even more) for the blog post (especially the legwork on pricing). I look forward to the day when "can we jump on a call?" sales processes are well and truly dead and self-service and transparent pricing is the norm.
Check this out for real-time query speed testing: http://cloudharmony.com/dnstest
(And yeah, looks like GoDaddy is a solid "Test failed" still...)
Funny note after running the test a few times--the worst performing provider is the one whose salespeople contact me the most...