> Don't the big players penalize mail coming from hosts?

Ftfy. :)

Yes, they do, unfortunately. I am still hoping for some regulation / fine to put an end to this.

Me too! You're in for a lot of pain, especially in the beginning, when trying to host your own mail server. Big players just dropping mails (Microsoft), local authorities refusing your mails (even on the postmaster inbox) and if your mail goes through it might still go straight to the spam folder. Granted, I'm using an .xyz domain, but I'm not sure how big of a role this really plays. Interestingly I didn't have problems with Google's mail servers so far.

I remember hearing that Google really downgrades the search rankings of .xyz domains. Not sure how it goes for email though.

I've not yet found this to be an issue with personal mails. If you're planning on setting up whatever system that needs to send _lots_ of mails, something else might be better indeed.