There should be access to a range of activities, and of course the holiday can largely be budgeted for in advance.
Disadvantages are less tangible.
Having paid to be there, it can seem pointless to explore outside the resort. There are reports of feeling a wimp if you don't use the childcare provided, and of intense parental competitiveness, focusing on evening rounds of Trivial Pursuits. And these holidays are not cheap. Before shelling out, it's worth thinking through exactly what you want from a resort. At Sunsail the figure is around 700 for an adult 570 for a child.