I have the IMAP option (and using it on my iPhone and Mail.app), so it is live... though only to select accounts - dunno how they decide which ones get it first though.
Labels are seen as folders on the mail client, starred messages as flagged, etc... Google did a good job.
I confirm, I do not see this option in settings yet.
Just checked and it's there... "Forwarding and POP/IMAP"