Nai Yang is a part of Phuket, that has remained discreet and quite natural. You won't find bars and restaurants lined up all along here, because it's included as part of the small Sirinat National Park, that is adjacent to the island's airport. Therefore, the surrounding area is protected and it's that much better, so hopefully it will stay that way.
Despite being so close to the airport, I didn't feel like the beach was too loud. Nai Yang is a beach that is rather appropriate for people who are traveling as a family, as evidenced by horses for taking walks on the beach, unless you are the rather romantic type waiting for the sunset.
In any case, it's a beach that feels intimate, first because it's large and it isn't usually crowded so it's comfortable, and also because it's lined with tall trees and I love this feeling of a beach that's exotic and not overused. On the other hand, this isn't where I come to bathe.