Just completed a week stay at the Westin Denerau and it is a great resort. The oldest and nicest of the Denerau resorts. The newer resorts are built higher density and are all much the same (Radisson, Sofitel, Hilton, etc.) and quite good quality overall. Great weather in the dry season (not sure about the rainy season, they clearly get some serious rain).

The Sheraton is recently renovated and has the best restaurant in Fiji (Flying Fish from Sydney, with pretty much identical food/service to Sydney -- good enough to be a destination restaurant, truly world class). Otherwise the Westin has 2 good restaurants, the Steakhouse which has a good wine list, and a Japanese restaurant with good sashimi.

Overall much better than Bali, Tahiti or Hawaii, at least to my taste. The Fijians are very friendly and even though it is "island time" they actually work pretty hard to serve guests. The Westin is quite a well run resort and worth seeking out.