This place is everything the pictures show. It is extremely unique and a genuinely awesome stay. To anyone planning to go, keep in mind that you really are in a tree (though obviously surrounded by luxury). You walk outside to go from the bedroom to the bathroom, the kitchen is entirely outside, you walk up a small spiraling staircase to get to your car, etc. While we had very few issues with bugs or anything like that, someone who is much more of an inside person might not be super comfortable (but then why would you want to stay in a treehouse if it didn't feel outdoorsy?).
The place itself was awesome. All the construction and furniture were impressive and solid. The bathroom was just as nice as any bathroom you'd expect. The filtered water dispenser was a HUGE plus after a long day at the beach or hiking in the heat.
We slept with the screen down and the doors open most nights and found it peaceful. I sleep hot, but never at any point was I uncomfortable. The temperature during our entire stay was perfect, and that seems to be the norm due to the elevation. The sounds of the forest surround you and when you're in the hot tub, you feel like you're in the middle of the forest.
The location was really perfect too. One of the appeals of the Big Island is that it's less populated and more open, but Kailua-Kona has everything you need (including a Costco and a great liquor store called Kona Wine Market), and is only 10-20 minutes away. Keep in mind, the property itself is definitely a shared space, and you don't always feel 100% private (such as on the walk from the bathroom to the bedroom), but it wasn't a huge issue for us, especially with the provided bathrobes.
Jeff was a really outstanding host. Extremely quick to respond and helpful.