I did a hobby project, a cross platform app controlling WeMo smart switches. Due to using FLTK_rs it works on Windows, Linux and macOS. Was amazed how quickly the code works after compiling. A lot of time is saved in development due to less debugging.
Many of us have. I enjoy KDE but COSMIC looks very slick and when listening to the developers it sounds like it’s really thought through. They have considered so many details. For selfish reasons I’m glad to see it’s already being worked on for openSuse.