I have never heard anyone who has used Vulkan actually advocate for it. But I have heard a lot of good things from Graphics Developers on Metal.

This isn't to say Vulkan is bad, everyone seems to be saying "In Vulkan, You really needs to know what you are doing".

Metal the API has some elegance in it, but the target range of hardware is controllable and way more limited than what Vulkan was designed for. Apple can choose what graphics goes into their Macs and iPhones, collaborate with the mobile GPU provider, etc.

Only on HN.

All major graphics middleware and image manipulation applications, are already Metal aware.