We stayed at the Kea Lani a couple years ago and would absolutely recommend it as an ideal destination. The rooms are excellent. Food was very good. They did a nice job with the pools by spliting off families from couples. Families hang out around the upper pool with the slide and its lower end kiddie pools. Couples hang out around the "other" pool. I didn't see much of it given were were there with the kids. The beach is very private and quiet. You will not see a lot of traffic there.

We did try breakfast at each of the three hotels. IIRC the GW was the best breakfast. 4Seasons breakfast was a bit tired compared to the KL and GW.

GW is a destination hotel. There is a lot to do there. It has a real resort feel to it. If you want a private and quiet time together, you will be less likely to find it here. If you're looking for an active vacation - this could be a good place. Also, you will find lots of Japanese couples for their weddings in the GW chapel.

4Seasons is a quiet location for a low key vacation. I didn't see much there and I didn't see a whole lot going on. But then, we didn't spend much time there (just breakfast). My feel was this is more a destination for more "mature" couples (i.e., older folks).

Would I go to Kea Lani again? In a heart beat!