We have stayed at both and both are great. With kids, we prefer the Dolphin because it has more of the things, like quick service food and ice cream shop and arcade, and better proximity to the Grotto pool and playground, that we want for the kids. If it were an adults only trip, I would say go with the Swan if a smaller quieter hotel with slightly larger beds appeals to you. We have found that Swan rates are slightly higher than Dolphin rates, so that might be a factor as well. Sevice was excellent at both hotels.