Just my review :)
Unibox is a good application with the best interface and a interesting approach, it sort email by people, it is not the only one that use this approach (e.g 4th Office), but it is the most stable and clean, this application really need a snooze feature (e.g Spark) and calendar integration to be great, also a easy way to star messages, if you pull from the top it show some icons, for search, star, unread,.... if you pull more it show as categories with + sign from where you can choose different filtering options, in my opinion it should have stop at showing only icons and allow you to click on icon, for the desired function, for a better and more cleaner interface, also it lacks export option (e.g dispatch), this is not as vital as snoozing and calendar integration, but it can be nice to have it, there are free options that does everything Unibox does, because of the interface if you add all this functionality i believe it will become one the best email options, otherwise it does not worth the money,