I’ve been using FastMail for over a year now and am delighted to hear that the long awaited IMAP email push is now available. That means default iOS mail client can receive push notifications like yahoo and other mail providers.
Push email will happen automatically for existing users and if you already have iOS configured with FastMail IMAP, you’ll just start benefiting from the change without doing anything extra.
I strongly recommend you try Fastmail if you are worried about security and about your email being parsed by servers for advertisements(Gmail).