Datai v FS
I do not understand why everyone is saying that the Datai beach is better than FS! The FS beach is a mile long and is about as wide as south beach in Miami. If you take a pool villa, you essentially have your own patch patch of beach with loungers and private pool.
This does not mean that I do not like The Datai - I love it (the End Suites are the best, or The Datai Suite)- but it is a totally different experience - right in the rain forest - but only about 30 mins by car from FS.
What we do is stay 4 nights at The Datai then move to the FS Langkawi - the perfect balance between an inland resort with beach and a seriously good beach resort (with one of the best spas ever).