We loved the Andaman and the great upgrad we received at the Sheraton Langkawi. The service at the Sheraton was not perfect but it was and excellent stay and we promised we are going back to Langkawi soon.
The daytrips were wonderful and much cheaper compared to the trips in thailand.
Langkawi is really worth a visit.
I just booked the LM Khao Lak with BRG for 2500THB++ next month.
The JW Marriott Khao Lak is also getting very good reviews. I will also stay at the JW for 2 nights.