We absolutely LOVED staying at Mary's place! We weren't originally planning on spending more than half a day on Waiheke, but are so so so glad we did! The cabin we stayed in was very cozy, and Mary kept us well supplied with coffee and treats. The views over the bay were beautiful, and it was a quick 15 minute walk into town. Palm Beach was beautiful and well, and just a 20 minute walk in the other direction. I don't think I have ever seen stars as bright as those I saw on Waiheke!
Would highly recommend! Next time I'm back in NZ I'll carve out more time in Waiheke.