Kiwi: A next generation e-mail client, built for IMAP and Mac OS X Kiwi is an outgrowth of the MailCore open-source Cocoa project. It aims to provide something that's generally lacking in the Mac experience to date: A truly kick-ass IMAP mail client. An interesting article on the developer's blog explains some background about why IMAP is so slow on the Mac. I'm bookmarking this site and keeping my fingers crossed that Kiwi actually does bear fruit.