Yup. At Sendbloom.co we have used Dart to build a tool that is used by sales people to send out email campaigns. The tool is inspired by quartz composer/Max MSP's interaction paradigms (drag-and-drop visual programming).
As someone else mentioned, Dart code can be fairly verbose, but it is very readable and programming with it is a joy when compared to writing vanilla javascript/jquery.
I'd be happy to answer if you have any other questions about Dart.