Admittedly, I haven't flown in Asia, South America, the Pacific nor southern Africa, but from memory, Australian ATC is generally significantly better than most other places that I've flown in. Rate of delivery, use of standard phraseology and accuracy are generally better.
Naples on a stormy afternoon or any of the Greek island ATC on a Summer's day = carnage. Anywhere south of Florida to the Caribbean on January 2nd is an absolute nightmare.