One point that I hasn't thought of until it happened to me: I took my car in to be serviced. My primary email address is on a .org domain. I read out the email

One point that I hasn't thought of until it happened to me: I took my car in to be serviced. My primary email address is on a .org domain. I read out the email address, and the .org bit completely flummoxed the person booking my car in, and she must see 20+ people a day with email addresses. She wrote "<myname>@<mydomain>." and paused. I repeated, "dot org", and she continued to type ".org.com". I think with a purely technical audience, you have much more freedom with the TLD. However with anything less, you may struggle. Remember even popular non-.com's like Wikipedia are probably accessed much more via Google than by typing wikipedia.org.