The GoPayment card reader was the bulkiest of the four mobile payment processors we tested, but it was also the least likely to swivel around while we swiped a card. The GoPayment app isn't as good as the reader. On the upside, it supports multiple user accounts, in case several people will be taking payments for you. But you can't waive signatures for small transactions, and an odd split divides the tasks that you can accomplish via the app and those that you can do on the GoPayment website. The website enables you to search for and view transactions, as well as generate reports; you can also set up recurring payments. But you can't view an itemized receipt that shows prices, taxes, and tips--you can see these details only on the app.