But Hainan Island is always famous for its sun and beaches only. If someone is planning for going there, you should have this expectation in your mind. It couldn't be compared to Thailand as BKK has got lots of shoppings and varieties of food. Sanya is only a developing tourist city, 5 or 6 stars hotels are still underway, without major shopping malls.
More apple to apple comparison, Bali is a little bit more closer to what Sanya is trying to offer.
If you want a relaxing holiday, you can consider staying at Banyan Tree Villa all the time. But if you are looking for good food and shopping, please do not go to Sanya.
I've just been to Sanya and stayed at Ritz Carlton. We also visited Hilton as it's just right next to Ritz (we were walking around Ritz and arrived Hilton without even noticing it).
I think Ritz is newer and much more grand than Hilton. Rooms are also bigger. We went with our 3.5 year old son and we think Ritz is very children friendly. The pools are also nice, especially the inifinity pool located right on the beach.
The Kids Room in Hilton looks a bit aged and the toilets next to the Kids Room are very old, unlike the common area toilets in Ritz, which are all very new and stylish. I did not regret staying at Ritz Carlton.