I have friends working for Telerik which was bought by Progress. They feel pretty happy so far and Telerik are doing well, though they had to drop native script after react occupied the entire compile js2native space.
My biggest complaint is how unresponsive they are to fixing bugs. After reported it may be months or a year before you see it fixed.
What I dont know is if that is common in that "ui component" sector?
I think this is why almost nobody uses closed-source libraries. Having to pay isn't the biggest problem: it's not being able to fix issues like these yourself.