The ease at which I was able use it after just one training session! It's so much better than using paper planners or sticky notes - my clients love being notified when an appointment is scheduled via text message/email etc., plus they don't have clutter cluttering up their desks like with physical calendars (and if someone forgets about something important happening while away then there are no worries!) I like how easy it is when using my phone or computer! It makes everything so much easier with one click instead having me go back through multiple steps just because i don't have internet at home sometimes (especially during hurricane season). If there was an option where they could send reminders via email without needing access to their website then life would be perfect :) but other than those few things its great!!