Just come back from 3 nights here (combined with 3 nights at the Ren in Mai Khao). The Nai Yang property is very nicely done. Lovely resort and the staff were excellent (with the exception of the pool attendants the which we found to be a bit inattentive).
The restaurants both good, and a nice happy hour in each bar which made drinking affordable. As already mentioned here no breakfast for elites but a 20% discount on F&B which I think would be a wonderful benefit if it could be expanded to all resorts Worldwide. As Platinum who generally stays in resorts or at weekends in cities I feel a bit undervalued generally at Marriotts but the 20% helped alot and also encouraged me to spend more in the hotel outlets.
We got a nice room upgrade to a Pool Cabana room which was one of the rooms in the new building.
All in all a lovely stay, but the hotel is VERY quiet so may not suit everyone. We loved it.