[dippersauce]

I cannot speak for the other poster, but there are several levels where consistency is significantly better. The GUI is of course the most noticeable, especially as the “iOS-ification” of macOS continues. But for a developer, the methods you interact with are more consistent across platforms and apps. Porting an app between iOS and macOS can be as simple as changing a few method names and setting a new target in XCode. For the most part one can assume things like app bundle layouts and where files will be dropped on the system. Most of this consistency lies parallel to where Apple enforces it, which comes with its own downsides.

That consistency isn’t absolute though, rough spots like the boundary between Mach and the BSD components still exist.