We've stayed at three, some years ago.
Pahio at Ka'Eo Kai, Alii Kai, and the Cliffs. All are comfortable, spacious, luxurious lodging. The activities program at the Pahio is by far the best. However, with a little net surfing or local inquiry, you can book your own activities.
Princeville is an exclusive residential area on a high cliff overlooking the ocean and adjacent to two golf courses. There's no beach you can walk to easily, but it's a great location for a quick drive to Kileaua Lighthouse, Ke'e beach, and the Kalalau Trail.
The Alii Kai and the Cliffs are almost across the street from each other. Some of the Alii Kai units have lanai which nearly overhang the cliff.
A caution for newbies who may reach Kaua'i late at night after a long flight from the east coast, a wait for an inter island flight and rental car pickup: you'll be tired and sleepy. It may not be late by island time, but it will be for you and the drive from Lihue is long, dark, and has few sign posts. Map out your directions in advance. Maps are available through AAA, your car rental, or on the web. But I particularly recommend the maps offered by this commercial website:
click here. We got our copy compliments of one of the resorts.