This is the first time that I have read a questionable review concerning TRC. They are the upper tier of RCI and handle a more luxury type of resort/villa/house. You can only access them through a membership with certain timeshare resorts. Yes, they do charge more, but the services available and resort directory is much different than RCI. They do have RCI's inventory too, if you want.
Some other forums only have good reviews and experiences to report. While I did not get a chance to use them, they were very knowledgable over the phone and helped me at that time by recommending that I not deposit a week since the resort I wanted only had rare availability. I appreciated that.
Also, in addition to the Grand Mayan, the Grand Bliss level also trades with TRC.