Their IMAP interface is both standards compliant and fully functional. I'm not terribly fond of the Gmail web/native apps either, so I just don't use them (though I do occasionally hop on the web app when my client isn't searching the email as effectively as google does).
With 2FA it can be a bit more work adding devices, but it's not a deal breaker for me.
Also when you try to write drafts in Thunderbird for Gmail, it stores them in such a way as each saved draft turns into part of the conversation (WTF?!) It makes conversations totally unreadable.
I quite gmail years ago and do not miss their broken IMAP implementation.
Edit: my point about standards compliance for gmail imap was purely about it actually working with third party clients, I've always known that it doesn't conceptually work the same way as a standard imap server.
And I don't like 2FA either. It's a hassle and never, ever, worth my time or energy. There was one gaming service (I think it was an MMO) that demanded 2FA or bust. I don't use that service and never will.
That seems to be a rather dangerous position to hold these days. I personally dislike that googles 2FA is SMS based (unless there's a way to use e.g. Authy with it that I'm unaware of), but still seems that the only way to be reasonably safe is a strong password and 2FA.
I'll add that The authy app on the Apple Watch has made 2FA for services that support it rather painless.
I think this is incorrect, at least provided you're using Chrome. The implementation was buggy somewhere in the chain the last time I tried it, but it's there.