QTP is a functional testing tool that allows saving screenshots during testing and has an easy-to-use interface. It is best for technical and non-technical users but only runs on Windows and not all browsers. Selenium is an open source framework for testing web applications that can be used with other tools through integration and has low system resource usage, but only supports browser-based tests and has limited popup window support. Both tools have advantages and disadvantages depending on the nature and browser support needs of the application being tested.