For many years, there were, at best, rudimentary and semi-functional Mac versions of Outlook, which created a self-fulfilling cycle that the Mac was not ready for or worthy of use in the enterprise. Outlook and the Mac have a long and ugly history.
This is great news if you live exclusively in an Exchange environment, but you may want to mute your celebration if you also deal with other calendars and contact lists created elsewhere. The latest surprise release of Outlook for Mac 15.3 is largely what you'd hope to get in an Outlook refresh: At long last, a version that looks and works almost identically to the Windows version.