Comment by LinuxBender

Anycast, gslb behavior, standard records, short logging, probably UltraDNS or maybe Dyn if you don't mind that Oracle purchased them. I don't know what you mean by cost effective. All the commercial providers can get expensive depending on how heavily requested your DNS records are. You would need to negotiate pricing. As for log retention, regardless of vendor that is something you would have to get them to put in writing in a mutually signed / counter-signed contract reviewed by your lawyers. Companies can say anything but it means nothing until it is in legal documents.