I tried KiCAD, but having used Altium for 26 years, I’m sticking with Altium. KiCAD could not do simple things like assign nets to arbitrary polygons, which is critical for RF layouts. The DRC was really lacking too.

Of course it’s probably great for an open source project, but I don’t know anyone using it professionally. We have 20 Altium license at work, and I have one at home for my consulting business. Even at $2k/year maintenance, that’s cheap compared to the other RF software I use.

The whole problem with free CAD software is you’ll never get the cross discipline skills needed to develop it without paying someone. For example you need an expert at electromagnetics AND scientific programming AND UI design, etc. That’s a full time job, not a hobby. There is a ton of domain specific knowledge.