To quote the article:

  Did they work? Yes! Performance on lightly loaded systems was about the same as OSSpinLock but on loaded ones, they provided massively better responsiveness. They also did something extremely useful for laptop users: they cut down power consumption as a lot less cycles were wasted having the CPUs spinning on locks that couldn’t be acquired.

To no one's surprise, one has to use Apple's undocumented APIs to be able to match Safari's power use.