
Exchange operators generally make their money by charging timeshare owners fees for exchange services. These fees typically include annual membership fees, exchange fees, and fees for guest certificates for those times when you want to allow friends or family members to use your timeshare.
When it comes to exchanges, there is no one exchange that is "better" than others. Some exchange operators are affiliated with more resort locations, so they might have more inventory available for exchange, but remember that when it comes to exchanging, your ultimate goal is to travel where you want and when you want, and preferably to a resort of equal or better quality than your home resort.