I stayed at Napili Surf at the beginning of August 2013 but didn't write a review because I really had nothing to add to what others are saying. I returned almost exactly a year later (August 2014) and I think I can now provide some useful information.
First off, everything you read from other reviewers is true. The property is brilliantly maintained --one of the best managed places at which I've ever stayed. Good snorkeling on the beach and good swimming. The kitchens are very well stocked with pots, pans, plates, etc. and perfectly suited for self catering. The cleaning staff do a great job and all the staff are very friendly.
I rented a car but really, if you are just there for a relaxing beach vacation and are not interested is doing things like the road to Hana or seeing dawn on the volcano, and if you are content to self cater, you could skip the car, take a taxi to and from the airport, and make one taxi trip to the Napili market for supplies. There are local buses but really, if you want to see the island you will need a car.
For families with young children or older couples who want a relaxing stay on a great beach in an extraordinarily well maintained property Napili Surf is highly recommended. Younger couples may prefer the action of a resort along Kaanapili Beach/Whalers Village area. I do not.
The resort has four buildings, three of which overlook a very spacious lawn and have a full or partial view of the ocean. Of those three buildings two face North East and one, the Ocean View Studios building, faces North West. The fourth building, the Garden View Studios building, looks over a narrow lawn at a high hedge, and faces North West. I have now stayed, in August, in a Partial Ocean View room that faces NE, and in a Garden View room that faces NW
On the air conditioning issue: In the Partial Ocean View room facing NE the breeze did a great deal to cool off the room (prevailing trade winds blow from the NE direction) I was quite comfortable. In the Garden View room you get a lot less breeze and the room was definitely a lot warmer at night. The Garden View rooms are significantly cheaper and significantly hotter, at least in August. If you want to maximize breeze through the room NE facing buildings are better. If you are in a NW facing room you might be better off on the ground floor since the lanais extend out into the lawn a bit and you get more wind. On the second floor the lanais do not extend out, and the breeze is blocked.
On privacy: The ground floor rooms are obviously not as private as the second floor rooms, because people will be walking by all the time and you will have your drapes open for the breeze. If you have a ground floor room right in front of the pool in the Garden View rooms you will have people sitting around the pool just a few metres from your lanai. On the other hand if you have kids who will use the pool having a room right in front of the pool allows you to sit on your lanai and keep an eye on them. For privacy avoid rooms 121-124. Rooms 127-129 would be far more private. On the other hand to have the pool right in front of your lanai so you can keep an eye on the kids rooms 121-124 are for you. The other pool, on the big lawn, is not so close to the buildings so you don't have the same issue.I solved the privacy issue by asking for a room on the second floor.
On the noise issue: Sure, all the windows are open and people are sitting out on their lanais,so you hear other guests. I guess that from time to time some guests are going to be louder than you would like, but my experience of 25 nights over two years is that loud guests are a rare event. Most people seem to be repeat visitors and very respectful.
Highly Recommended