A good Exchange Client. Well worth the $15.
Ranked in these QuestionsQuestion Ranking
Pro Supports latest ActiveSync protocols
As of this writing (Sept. 2016) it supports version 16.
Pro Convenient theme options
The black theme is easy on the battery and eyes.
Pro Good customization
But not so many you have to read and dig through documentation to do what you want.
Pro Supports Outlook category colors, Outlook for Android doesn't
Pro Very reliable
Pro Extremely customisable
Con Not free
Con Not Cross-platform at all
Only has an Android app. No Windows, Mac versions available.