I like that it's available as an online web-based tool, which allows me to access from anywhere! It also helps with our employees' time management by keeping track of all their appointments for them - no more lost paperwork or misplacing reminders (which we used in paper form).
The interface could be improved though; some features are difficult/impossible without using 3rd party software such as Excel & Outlook addins / plugins etc., but this isn't necessarily bad if you have those tools already installed elsewhere anyway? We're looking at migrating away completely now because there were too many issues managing employee attendance via email alone when trying out other systems previously so far everything has been great about yellowschedule since switching over last year!!