Gmail is more than just mail, it's also integration with other Google services, like calendar. How does Fastmail fare in that regard?

FastMail supports CalDAV. I use my FastMail calendar with Thunderbird (Lightning) and on my iPhone; works great. They also support CardDAV for contacts. /satisfied FM customer since ~2008 or so

I had to purchase a CalDAV and CardDAV app (which were extremely cheap, mind) for Android, so it's not quite as plug'n'play there.

Why is jjawssd's (sister) comment dead? Davdroid works great and is free (as in beer and speech), though I would encourage people to donate if it's useful to you.

I wouldn't know, I have a self-hosted calendar. From the little I've seen, though, the calendar part of Fastmail is very good too.

Which self-hosted calendar do you use? would you recommend it? I'm in the market for a new one, but the current offerings that I've seen aren't great.

I use Radicale and find it great, but there's no UI, so you need to use whatever client you want that supports CalDAV (I use Lightning and the calendar on my phone). Lately I've been liking Nextcloud a lot, and that's a one-stop solution for lots of things, so nowadays I would recommend that if you have a home server or want to pay someone to host it.

Thanks!

I've looked at nextcloud, but IIRC, you have to have the whole suite installed, right? I'd love a way to just use the calendar function.

Yeah, you do. As I said above, Fastmail's calendar is very good too, and you can load your self-hosted/CalDAV calendars into it, so that's a good option.