On my backpacker trip across NZ, The Tree House was one of my absolute favourite hostels.
All the facilities (kitchen, bath, washer etc.) are good.
The rooms are really good.
Lying in the bean bags under the skylight was amazing.
The landscape around the house is fantastic - forest, lake, hiking trail etc.
The wall clock with only one hand saying nothing but "now" was inspiring.
But in my opinion the best thing is the whole mood in the place. Everything is so relaxed and laid back, and you feel right at home straight away. I think this is very much due to the host family. We got a warm welcome and enjoyed the company during our stay.
During my trip this was the hostel we stayed at the longest. When I am returning to NZ, I will be staying there again!