I found RCI's "resort recognition program" page. It states: "The RCI® Resort Recognition Program honors affiliated resorts that consistently offer superior vacation experiences. These awards are given based on comment card scores from RCI subscribing members who have vacationed at these properties."
II actually has listed out requirements that a resort must meet to gain their recognition levels.
Interval International Elite Resorts
Interval International Elite Resorts are the very best of Interval’s network, providing an extraordinary vacation experience, exceptional service, and luxurious features and appointments. They are identified by the lotus, a symbol of purity and perfection
Interval International Premier Resorts
Interval International Premier Resorts, debuting as the highest level of recognition, provide an outstanding vacation experience, with state-of-the-art conveniences, and modern features and appointments. They are identified by the laurel, a symbol of distinction, high standards and status.
Within this level of recognition,
Premier Boutique Resorts provide an outstanding vacation experience, with excellent accommodations in desirable locations, and limited on-site amenities.
Interval International Select Resorts
Interval International Select Resorts provide a great vacation experience, and are distinguished by a comfortable and homelike atmosphere. As such, they are identified by the pineapple, a centuries-old symbol of hospitality, welcome, friendliness, and warmth.
Within this level of recognition,
Select Boutique Resorts provide a great vacation experience, with comfortable, homelike accommodations in desirable locations, and limited on-site amenities.