Google does derive real revenue from me, but not so much via their advertising business.
Edit: FastMail is a very good email service, BTW.
I found the tool to be fast, comprehensive, and the partial migration was very effective.
One the search front, I've been finding https://www.startpage.com/ to be a really nice alternative to DDG.
I receive more spam in my inbox than in Google Mail (I used Google Apps), but it's not extreme. Typically two or three spam mails per week.
Of course, you get a lot back. As you say, I better web interface and standards-conforming IMAP.
Honestly, DDG surpassed google search years ago. I've preferred Firefox for a long time, and Fastmail's UI and service is incredibly superior to GMail. I guess the cost might be the only downside.
While I use Fastmail with my own domain, it is not self-hosted. My MX records point to Fastmail's servers.
I've been tempted to add the support in myself, however I do not have any experience with the elementary codebase or Vala, so a cryptographic system would be a very poor choice for a first project!
I mainly use IMAP via Mail.app on my laptop and phone, Pantheon Mail (formerly Geary) on my desktop. I use PGP wherever I can. I haven't received any spam at all yet, so I can't comment on how their spam filters compare to Gmail. I maintain a zero inbox – important stuff gets archived, and everything else is deleted. This means that I don't miss Gmail's search feature as hardly keep any emails. Obviously your mileage may vary here. They also support CalDAV and CardDAV – so all of my notes, contacts, calendar items etc. are synced across my devices.
I've moved from Google completely, and for the most part, I don't really miss them all that much.
- Search -> DuckDuckGo (I do miss Google here – DDG's search results pale in comparison)
- Gmail -> Fastmail
- Maps -> Citymapper and Apple Maps
- Chrome -> Safari on macOS, Firefox on everything else (my experience with FF is a bit 'meh' – it was incredibly laggy on my work laptop, but runs great on my desktop)