Not that I've actually used any of these APIs, but supposedly Metal is the best designed Graphics API by a decent margin, it's just handicapped severely by how insular they and their ecosystem are.
Depends on what you're comparing to. Many people will point to OpenGL and Vulkan as comparisons, which is fair. But those are just the Open Source alternatives, and Metal itself is a proprietary solution competing against other well-designed alternatives like DirectX and NVN.
I think Metal's ergonomics advantage is a much slimmer lead when you consider the other high-level APIs it competes with.
