For what it is worth, I had the opportunity of using "Starclass" on a trip to Hawaii and I must admit that after what I had prevously heard I definitely had reservations.
However, the whole experience turned out to be nothing less than superb with the seating as good and probably better than most and the cabin staff exceptional.
All in all a great trip and I have numerous overseas travels under my belt with many airlines to make comparisons.
If you get the opportunity to use "Starclass" on Jetstar don't hesitate.