Quality of Service (QoS) has gained more importance with the increase in usage and adoption of web services. In recent years, various tools and techniques developed for measurement and evaluation of QoS of web services. There are commercial as well as open-source tools available today which are being used for monitoring and testing QoS for web services. These tools facilitate in QoS measurement and analysis and are helpful in evaluation of service performance in real-time network. In this paper, we describe three popular open-source tools and compare them in terms of features, usability, performance, and software requirements. Results of the comparison will help in adoption and usage of these tools, and also promote development and usage of open-source web service testing tools.