Hi Daragh,
Selenium is very popular and largely used for GUI testing. I think it is good for testing because I see it as a good solution for the Continuous Integration and DevOps principles which are the current trends and the future in software. For example, on a Java based web application a desired approach would be to have both the code and the tests written in Java and not a specific tool used only for tests.
I also consider that dominance of Selenium will continue due to its costs for companies. Many companies don’t or can’t invest much money into expensive tools and an open-source tool seems to be a good solution. Of course, in practice it is not totally free compared to a paid tool because when needed, workarounds must be developed for some limitations (e.g. handling windows that are not identified by Selenium). Selenium has also advantages in terms of customization, which makes it also a strong player in the automation tool competition.
From my point of view the dominance is good for testing and I have seen vendors that are integrating Selenium into their paid tools. This provides a better flexibility for testing and it combines Selenium’s advantages with the ones offered by the paid tool. In the future, I think Selenium will be something like a bridge between free and paid tools.
Regards,
Alin