Koh Yao Yai is best for anyone seeking tropical getaway in beautiful settings that are far, far away from the crowds. Koh Yai Yai in general is dwarfed by the fame of Koh Yao Noi, and that island is often overlooked because of Phi Phi and Phuket. The end result is a beautiful island that's been allowed an escape from resort style colonialisation. Let's hope it stays like that. In short, there is no "nightlife" on the island. Party goers and Full Moon chasers should stick to the more developed tourist spots.
Koh Yai Yai Village is one of the few resorts on Koh Yao Yai. It's located on a nice beach on the northwest corner of Koh Yai Yai. You can find it on google maps (8.033012,98.601308). The nice thing about the beach is the small number of wooden beach chairs, the view of Bird Island and the lack of sand fleas (some of the beaches further north have them).
Every room is a private villa surrounded in trees, ferns and foliage. Each villa has an outdoor salla. The fridge is in the salla area. Each room has a flat screen television mounted to the wall. The pillows are amazing. The bathroom has an open air shower with a rain style shower head. The shampoo, soap and conditioner are herbal. If any of them smell funny, make sure you ask to replace them because herbal soaps don't always keep well in tropical environments.
Do go to Koh Yao Yai Village is you want a secluded getaway. Do not go to Koh Yao Yai Village if you are on a budget. Do your best to bring a scooter to the island if you want to explore. The scooters on the island are pricey. You can bring a scooter or car to Koh Yao Yai from Phuket. The resort can help you arrange a spot on the ferry. Finding the ferry can also be difficult, so ask if you're not sure.
If you come to Koh Yao Yai without your own transportation, the resort can pick you up at the pier. But I highly recommend you bring something to explore the island.