We stayed at the Modern while my husband was in Honolulu on business. It was a gorgeous property - meticulously kept - and the rooms were a great size and very comfortable. The staff goes completely above and beyond to ensure you have a great stay. The hotel food, while very pricey, was amazing - everything we tried from breakfast to snacks to drinks to lunch/dinner was fabulous.
The only drawback is it is in a bit of a strange spot in Honolulu - not quite close enough to the true Waikiki area and there aren't a whole lot of nightlife/good restaurants around the hotel.
We did not try the nightclub at the hotel, but it's supposed to be one of the best on the island. We would definitely stay here again.