I especially liked Sprout Social's ability to organize your followers into categories, such as Twitter users who aren't very active. This allows a brand to weed out inactive users.
Sprout Social's reports are basic, especially when compared to reports from Simply Measured. But they lay out solid information in a very attractive package, and the data is exportable and customizable.
Scheduling posts across mulitple networks (Facebook, Twitter, LinkedIn, Google+) is simple, and the "Publishing" tab gives a nice outline of all your scheduled posts.
You can easily view your "history" with another Twitter user, not just a a recent conversation.
Very slick. It's easy to get where you're going -- even discovering features when first using it was a breeze. The tabs across the top of the interface also make it simple to get from one place to another quickly. Extra points for solid mobile apps and its iPad app.