Re: Depends on what you're doing
OSX is much, much faster than Windows for some workloads.
I doubt that. If the application code is well written then it should be running as fast as possible on the same CPUs. There are always edge-cases relating to I/O speed, networking, etc. but in most cases the OS no longer makes much difference and, indeed for things like video-encoding, Windows is easier to get hardware acceleration working.
Where MacOS generally shines is the integration of tools for certain workflows. For me, as a developer, I find the posix side of MacOS just so much more convenient, not least because of the path names.