There are quite a number of concepts I like in Mailbox, a new email app shortly to be release for iPhone. The use of swipe gestures is genius and so is the "snooze" function to hide emails for a defined time from your inbox. You got to love how that function is used in the last sequence of the video.
It reminds me a bit of the inbox rule I got wrong the other day in Mail.app. Instead of selecting that all conditions need to be met for the rule to be executed I left it at any. Since I was matching my email address my entire inbox all of the sudden was empty and everything got marked as read and moved to archive.
The concept of your inbox as a task list is obviously something I need to disagree with Mailbox on. Although I like the idea of determining the order in which emails are displayed yourself. Unfortunately and as so often Mailbox seemed to be geared towards GMail only and in particular Exchange users will not have the joy of using this app.