The ease with which I can quickly create sub accounts for my customers or assign them to an employee account without having to do it manually. It's not as user friendly on iOS at this point in time but if you're looking into using AM then be prepared because they have many features available such as accounting services, payroll management etc as well! Their customer support is unparalleled (they literally will work around the clock)!! If there are any issues please give them some slack - their team makes sure your issue gets resolved right away! You definitely want to get this product so that your teams efficiency increases by leaps and bounds when doing client billings/payroll processing. We've been able to cut down our staff hours significantly, eliminate manual data entry errors & make payments much easier than ever before with minimal risk.