The ease of use, how easy it is to view my schedule for upcoming appointments in real time so I can be prepared when an appointment comes up! It's also great that you don't need any special equipment or software - just log into their website from anywhere with internet access- even if its only through mobile data (like using wifi hotspots). Sometimes there are minor glitches but they quickly get resolved by contacting customer support via email/phone calls etc which takes care off issues very fastly & efficiently. This app works best where WiFi coverage is good enough such as cafes eetcetera allowing me to keep track of what needs doing next without having to rely solely upon phone reception while travelling around town.- keeping work organised whilst out working away from home.