No, although they may have some similarities they may differ in several important ways.

1) Some require you to pay the fee before searching for your exchange request.

2) Others are deposit first only

3) There are others that allow you to make your request before you relinquish your week.

4) Some are free to join while others may have an annual subscription and have different exchange fees.

5) Additionally, some may specialise at timeshare accomodation at a specific part of the world and have better availability than others that may suit a particular holiday requirement that you may have one year.