I've been using KiCad professionally for 2 years, and I'm pretty happy with it. I made a token effort to try some commercial offerings but at this point the transition cost seems higher than the benefit for the mid-range boards I'm making. Would likely be different if I were laying out big FPGAs with RF and DDR5.

I'm really looking forward to KiCad 6. Tried the nightlies and the UI improvements and all the little changes are really impressive. Was tempted to switch my work over to it but was scared of the inability to convert projects back to the KiCad 5 format.

My one major complaint coming from a software background is poor support for version control. KiCad is closer than most to working with standard tools due to its structured textual data formats. However the structures in the files are ordered by comparing the objects pointers so every time you launch KiCad and save it randomizes the order of everything causing massive spurious diffs. I've seen some people use pre-commit hooks and perl/sed scripts to try to fix the diffs but could never get them to work. I've been meaning to contribute a better sorting system but the prospect of building 30 C++ libraries from scratch on Windows triggered PTSD flashbacks.

In the mean time I've been using cadlab.io which is a GitHub-like for ECAD. It can make visual diffs of changes which is quite nice. It can be slow, though, and it has a weird rendering bug on Firefox that makes everything blurry sometimes.