It ties in easily with AD, does shared mailboxes, calendars, contact lists, meetings, automatic out of office, sorting, legal hold, archiving, backup etc rela

It ties in easily with AD, does shared mailboxes, calendars, contact lists, meetings, automatic out of office, sorting, legal hold, archiving, backup etc relatively easily without having to glue together a hundred different things. MS will support it & offers training. It can be managed easily by the same windows admins they have managing their AD infrastructure and desktop support.