My favorite part about www.scheduly.com is that not only can I view my services and appointments, but so can my clients.  As a newly-established photographer, working pretty much alone, it gives me an easy way to stay organized.  Since I work out of my house, and I don't have a receptionist, my clients can see what I offer, how much it costs, and when those services are available, without having to ask me a hundred questions!  I have invited many of my clients to join, and now instead of getting 50 phone calls with questions, I only get phone calls to book my services!