WordPress.org

I think that one year without addressing this major security concern is worth only one star:
http://wordpress.org/support/topic/plugin-configure-smtp-password-is-unencrypted-stored-and-printed-in-html

In the back of my mind, I wonder isn't this what oAuth 2.0 is for?

In any event, beware using this plugin at version 3.1. Your gmail password is not only in plaintext in your wp_options table, but anyone with access to the wp-admin settings can view your password by inspecting the HTML in their browser.