Until I did this, my deliverability, especially to GMail, was awful.
ezmlm, for example, will not let you subscribe/unsubscribe
I've been administering mail servers going back over 20 years and I wouldn't recommend it to anyone. The last 4 years or so, things have gotten a lot worse. Google and Microsoft are actively and deliberately making it harder for people to run their own mail servers.
Sure, setting up DKIM and SPF and whatnot isn't hard. But blackholing legitimate mail without any reason, without any form of notification or any possible appeal, well that's just appalling. And sure, Google & MS have tools to debug a subset of mail issues, but those don't even work unless your MTA is sending boatloads of mail to their servers.
People at Google might be the smartest under the sun, but they don’t understand email: It’s primarily a way for people to communicate with each other. In Google’s eyes it’s only a way to deliver advertising to end users.
Edited for typo
Oh no, they understand email very well. They're just arseholes who want to force "regular joe" and small business to use their services. This isn't some kind of accidental incompetence. There's no "whoops, sorry your mail isn't getting delivered, our bad!"-type situation going on. This is a deliberate strategy of making it as hard as possible for people to run their own mail servers.
Of course they hide behind the excuse that you might be a spammer. But given Google's massive resources, there's no way in hell they can't tell ham from spam.
I set up my mailserver, sent a testmail to Google, no spam or other stuff. I don't know if SPF or DKIM was even configured. (It now is of course)
And of course, not hosted at home.