Fiji: Lower Mamanuca islands

Lower Mamanuca islands are within only an hour from the ‘mainland’ Fiji and are peppered with the most expensive resorts (like Likuliku, Castaway, Mana, etc.) as well as crowds of people. I guess it’s nice to have a glass floor in your bedroom and jump to snorkel at any time, but is it worth 2-3K USD per night? I dunno…