I like that it has so many different options for each of our events! It's very user friendly as well - which is great when we have multiple people in charge at once (we can't always trust everyone!).
There aren't any downsides right now but maybe there will be later if they update things or add new functions/features? This software was used by us last year during one day camp where parents could sign up their children online before going into personlized classrooms with other kids who signed up through this website too.