iOS: Good luck not finding a Twitter client on iOS. You have so many choices that you would think developers would have no ground left to cover. Tweet7 found a new niche, however, by making a remarkably simple option for iOS 7.
The app gives you just your stream and one button to compose a tweet. If you want to access your messages, mentions or profile, however, you can do so with a gentle swipe from the right side of the screen to the left. Tweet7 breaks the screen up into three sections so what you get depends on where you swipe (see the image above for a breakdown).
Beyond that, you shouldn't expect much. If you want a fully featured Twitter client, check out our top pick for iOS. If you want a super-simple option that looks like it belongs with iOS 7, however, you can have it for $2.99.