Which one is better depends on the platform you're on.

We are not stuck on any particular platform, we target numerous platforms new and old. Using make, the target may determine which of those wonderful tools in our ever changing (improving, failing and obsoleting) ecosystem does the actual build.

    build:
	xcodebuild -target MyApp -configuration Release clean
	xcodebuild -target MyApp-universal -configuration Release-universal clean

But all I need to do is type make