Good app, but...
Yes, I think thats a good app to manage an Exchange mail account: useful, nice design, easy to configure an account and easy to use but... It has not a search function (with a specific field) and the calendar cannot updated directly... If you want to gain the 5th star, you have to improve your app with new features and utilities...
Aquer about
Inbox Pro, for Outlook, v2.0.1