One of the most powerful Tool for load testing (compared to Commercial or Open-Source solution)
It is a very flexible tool and allows much higher customization than commercial products.
It has since 3.X a very nice web report that provides very rich reporting.
It integrates very well with the development stack through Maven, Gradle, Jenkins, Bamboo...
It is very easily deployable or available on the clouds (AWS, Google, Azure)
It allows load testing a very large range of protocols with Core or Open Source or commercial plugins.
It has a recording feature that allows a huge gain when building a load test. It also has a lot of Extractors (JSON, HTML, Regex, CSS / JQuery ) that allow building very complex scenario easily and an IDE for building it and debugging it.
Its architecture in plugin allows extension that ranges from simple productivity extensions to complete plugin for new protocols.
But maybe the lack of undo/redo in the GUI.
And for beginners, the need to read the documentation and a certain learning curve.
Load testing Web applications based on J2E, PHP, ASP.NET technologies, Mobile Applications, Micro-Services based applications, Restful Webservices, Soap Webservices, Enterprise ERP, BI applications, Video Streaming servers.