gmail likes to flag some of my mail as spam despite having everything set up properly (TLS, dkim, sfp, PTR) . Some businesses have improperly configured MX, so you can't be too strict on the rules or you'll need manual intervention all the time.

Overall, it works fine I have been running various domain for about 10y now. Plus it contributes to the decentralization of email \o/

make your own: get a domain (15$ probably less for a year), get 2x tiny servers (around 10-15$ each) and deploy MX and IMAP services on your favorite OS. Takes a while to set it up but it's pretty awesome :3