Also, this wasn't mentioned in the first post of this thread, but its a new feature of iOS 7: You can add individual mailbox folders to the main mailboxes screen in the stock Mail app (click edit, and add the folders from your mail accounts). In iOS 6, you could only have inboxes on the main mailboxes screen.
Update with beta 2, you now get notifications for new mail in each mailbox folder (previously, notifications only worked for mail incoming to the inbox).
For example: I have my gmail set up so that MacRumors emails bypass my inbox and get sent to a MacRumors folder. In iOS 6, I would have to go under my Gmail account and scroll to my MacRumors folder to get to that new mail. In iOS 7, I am able to add that MacRumors folder directly to the main screen, so I no longer have to go searching for it. With beta 1, I would not get any popup notification that there was new mail in the MacRumors folder. With beta 2, I do get those popup notifications.