I have been using KiCad commercially for a number of years now.
Key driver for me was the ascii text based file formats where I felt much more in control of my destiny so to speak.
Particularly when I was investing time and effort in library symbols and footprints I wanted to be sure that I could access and control that data (now and in the future) and not be locked in to having to use some vendor proprietary DB format.
On that note I really like the ability to version control my libraries and designs with standard tools like Git and being able to see the changes with standard text diff tools.