Our users initially loved the new Outlook app for Android when we rolled it out to them, but after using it for a few months users contantly complain about their calendar showing up as blank when they go to check it. A few hours later it will be there with all their appointments. Many people now have OWA and Outlook installed on the same device so they have a backup in case they can't check their calendars in Outlook. There shouldn't be any second guessing here, calendars should cache on the device and receive updates as needed. Whether if it's spotty interent or some other problem they should have comfort in knowing that they can always check their calendar for upcoming appointments. People live and die by their Outlook calendars in my company. We're really trying to push people away from ActiveSync solutions and towards the Office Apps for mobile but this is a major sticking point.