I like that selenium webdriver supports multiple browser automation with multiple languages. Community support is great and usually if an challenges faced it

Ease of automating web applications, different options to locate web elements, open source and having the ability to integrate with testing frameworks like TestNG

One best thing to describe is the recording which allows users to record the session and create automation accordingly. It's easy to start with - simply download it as an extension to the required browser, mainly for firefox and chrome, and start using the recorder - test the recording and you can automate things easily. The script can be easily generated based on the recorded part. It supports many languages to work upon without restrictions. One needs minimal knowledge of the language to work with Selenium. It's the best for the beginner in automation. It also has built-in file login Plug-in. If needed, one can easily debug and also create and set breakpoints according to the requirement.