1) their effect on spam filtering
2) monetization
3) privacy concerns
4) standards violations
5) misuse of reserved domains
6) unexpected behavior generally

To this list I will add one more: damage to internationalization. Previously, a name lookup that returned NXDOMAIN could be detected and processed in the language appropriate to the application. Now the lookup resolves to "sitefinder-idn.verisign.com" which is meaningless for most network services, and yields a Web page in English only for HTTP.

There was no confusion in my mind as I watched the transfer take place between sri-nic and Verisign. Vixie has it right. Administration of the DNS is a public trust, and VeriSign is the caretaker, not the owner. And now VeriSign has abused that trust.