The Royal Sands is a nice popular resort. That being said I wouldn't consider buying anything other than mid January-March or a summer week or Christmas or New Years weeks. In all cases you should only buy if you intend to use (not exchange) at least 50% of the time. Most Mexican resorts were sold as Right to Use because the laws there make it difficult for non Mexican Nationals to own deeded ocean front property. Some people actually prefer RTU because they know when the term ends and they don't have to worry about having to sell at that point.
The Royal Sands is a mandatory All Inclusive (AI) for those renting directly from the resort or exchanging in through RCI or II. AI is optional only for owners and for their guests. Owning at any of the royals means you will not be required to take the AI at any of the Royals even when exchanging in.
Tracey S.