The GUI experience on Linux suffers mostly from inconsistency when using applications written with different toolkits, awful font rendering, and a general sense of being in the uncanny valley if you're used to other desktops environments.
My first computer in the mid 90's was running Linux on the desktop, and aside from a smattering of Windows here and there for games throughout the years, I've mostly stuck with it. Using Windows and OSX isn't some revelation in usability these days. OSX is more aesthetically pleasing, and a bit more consistent I think, but otherwise I don't find it profoundly better than the Linux options. I don't think it's more discoverable, and certainly hasn't been more stable in my experience- and there are definitely features I miss going from Linux to OSX on the desktop.