The ease of use, customization options are endless - they have an awesome sales team who will walk you through everything in detail before purchasing! They also offer free trials that allow us to test it out ourselves without committing money first.
Their customer support can be hit or miss sometimes but I know when someone is working hard at solving our problem as opposed my having their own agenda (like charging me). We've been able solve most issues we had with them pretty quickly so far because there's always some new feature coming soon which solves all kinds problems/needs people might face within HRM department like attendance tracking etc.