Been snowboarding Turoa and Whakapapa for years. Frequently hard packed days, but when it's on it's on. Don't bother with the weekends unless you go hiking. A hike to the crater is one of the most rewarding things you will do. See the beautiful views, steaming crater lake and get fresh tracks all the way down. Take the camera. New lifts going in this year which should help the congestion.
The terrain park has some great kickers and rails. Half pipe is almost non existant.
Definitley the most unique terrain you will find any where in the world. Especially out west at Whakapapa.
Awesome nights out in Okakune (great food) or head to Scnapps in Natty Park. Hotties, live music, need I say more.