I used mail@firstname.lastname.name and sometimes even like the op "service"@firstname.lastname.name for some time. This lead into all kinds of trouble, social and technical. Social as in people did not understand why I "owned" "service"@..., why I did not have something like firstname.lastname@t-online.de/web.de/gmx.de/googlemail.de, that a third level domain is even possible, or they did not recognize .name.

Technical trouble was almost the same: Systems did not recognise the new at the time .name or Systems had trouble with third level domains. Somstimes I could sign up, but something in the backend broke and I never received mails.