Having been to both I believe you will greatly enjoy either destination. If you are looking for a smaller-quieter place for romance or eco tourism then Los Suenos is the place to be. If you are looking for blue waters and white sand beaches with great night life then Cancun is the place to be. My wife and I are very excited to be going back to Costa Rica in February and hope to take the kids in 2010. We'd like to take them to Cancun but I think they are too young and would have more fun in Costa Rica.