Nice enough but not great value for money
I recently stayed at Suanya with my two friends and we had a good time. However upon arrival the staff (who speak little to no English) noticed we only had three and gave us a triple room even though I booked the Quad. It was clearly available but they wouldn't let us have it because they wanted to wait and see if a 4 person group would come for the room. That soured the experience from the start.
The triple room is very small, with the beds pushed together from wall to wall. The outdoor shower was very nice though.
In terms of value for money I would say that Suanya is a bit on the expensive side, considering we saw other small bungalows available on the island between 250-500Baht/night.
The private beach is very small but nice enough. The only problem is that in the evening the trash men dump their rubbish right next to the Suanya resort for it to be sorted. This lead to the inevitable bits of plastics floating around in the water.
I would not stay at Suanya again because even though it wasn't too expensive, everything felt just a bit overpriced for what you actually get in return -- The rooms, the menu (100+ Baht for Som Tom!!), the scooter rental (400B versus 300 other places).
Our stay was pleasant enough but I think I'll try one of the other many places at Koh Kood next time.
Make sure to check out Sunset Bar -- there is a great atmosphere there; very casual and they have an all you can eat family style buffet each night for 200Baht. It's one of the few places to go at night on the island.