It's very easy to use and the app works perfectly. Reasonably priced service as well.
Ease-of-use, ability to do everything off your phone, and the 24/7 access to the entire client base at the tip of your fingers will help you prevent scheduling conflicts, improve revenue.
I have been using it for about 3 months now, going from pen and paper and manually typing up invoices it's a huge time saver when it comes to collecting payments and keeping records.