Flame on:
Well. Linc, let me explain why I chose Gmail. It has been around for a long time, it's operated by a stable company, it provides plenty of storage for archived email, it's free, and nobody told me until now that it doesn't comply with the IMAP standard.
Let me also explain why I directed my frustration at Apple and not Google. When I upgraded from Mountain Lion to Mavericks, it was the Mail app, not Gmail, that changed.The previously existing Mail app worked with Gmail or could be made to work with Gmail. There was no need to change it when the underlying OS changed, except as needed to use a new API.
Furthermore, if you're upset about ads, direct your frustration at Google, not me. I didn't put the ads there, and there aren't any ads in either the email I send or the email I receive. And it isn't only Gmail that invades your privacy.
I don't want to give up email, and I certainly don't want to use the Gmail web interface because it pretends to be smarter than I am.
Flame off.
1. I use Apple Mail to compose mail because I can get mail from multiple POP and IMAP servers, select which SMTP server to use, choose among different signatures, etc., and the Mail app was right there on the dock.
2. I use a "permanent email address" that does not store mail, but immediately forwards it wherever I told it to. I told it to forward to Gmail for reasons I enumerated above.
3. I use Apple Mail to fetch my mail from Gmail. I now have about 2GB of archived mail on the Google servers.
I've gone through the Sent folder and moved about ten thousand email messages from Sent to the custom folders that I had already moved them to before Mavericks. There are still about three thousand remaining and I don't remember where I originally archived them. Some of them may have multiple labels, but when I search them in Mail, the app only tells me they're in All Mail, and I don't know how to make Gmail tell me anything useful.
Can you suggest an email client that has the features I use in Apple Mail, and preferably can show the labels that Gmail attaches to each message?
Or is there another way out? If I manage to distribute the Sent messages to other folders, will they stay there? Will Apple Mail work properly after that? No, that's the wrong question. Will it do what I want without breaking something else?