Visited Amansara in July. I thought it was terrific. It is very small (~12 rooms). It is a fantastic way to see Angkor -- Aman takes care of everything for you. Keep in mind that you are going to Siem Reap to see the temples and that everything is organized around this. If you have not seen them, it is well worth the visit and there is no better way to go than with Aman.