I use it mostly to design microcontroller based projects. I started using Fritzing but was very frustrated with the lack of symbols in the library. I tried making my own, but it was very cumbersome. I decided to try something much more capable, so people here recommended KiCad. The learning curve was very high at first, but the payback is it's relatively easy to make schematic symbols and circuit board footprints. So, I use it initially to design my circuit layout in the schematic editor. Then I move to the PCB editor. They are two distinct things and require different techniques. I like that generating the required Gerber files is simple.