On iOS is still use the default Mail app, but on my two desktops the web app is fantastic.
I do use the Android app, though. It has exactly the same "not sexy but works" feel for a platform where making a decent web app is even harder.
I'd have to front it with something like "forwardemail" for catch-all though, but it'd still be cheaper per month. And O365 is quite nice, used to work with it.
@fastmail team: please make contact sync a thing in your app, I don't want to use $megacorp, but nothing else does it well (davx doesn't cut it)
I might be holding it wrong, but it's my only issue with FM as it is right now!
Weird obsession.
I'm annoyed by one thing: the font weights of the read email titles are a bit too heavy and black in the list of emails, making it unnecessarily hard to distinguish them from unread emails with a quick glance. The blue dot doesn't really help much IMO. Gmail with all of its faults still nails this.