It's free.
it's easy to Start with lot of documentation on its Website and on internet
it has a proxy feature to easily create test plan from browser navigation
It is easy to start up processes on other machines. It remote testing, can be done from GUI or console.
The scripts can be written in beanshell, java, or any jsr223 language ( groovy, Javascript, scala, jexl ...)
it has a lot of built- in samplers and thanks to its plugin architecture it's very Easy to add new ones or use any scripting engine to do what's missing
it has great user mailing list
it has very reactive support
it's now a top Level Apache project
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