> completely block all gTLDs. Screw 'em, they are 99.9999% spam

[citation urgently needed]

Anyway, in my own experience with many years of self-hosting mail - until giving up and going Fastmail a couple of years ago - the real problems were in sending. No matter what rigorous level of DKIM'ing and ip-hygiene and whatnot, Google and Microsoft - Microsoft to a grotesque degree - would randomly ditch incoming mails from my server. Would sometimes happen in the middle of a conversation thread, and for the most part without warning. The kind of person using Hotmail is typically not someone you can convince that the error lies in his end.