I think the Kauai Beach Club might be a better choice. Waikoloa has shopping across the street, but I'm not to excited about the beach. Waikoloa is nice but I prefer the Kauai Beach Club and Ko Olina on Oahu better. If you are looking for night life then Ko Olina is about 20 miles out of Honolulu where Waikoloa is about 20 miles from Kona. You will enjoy any of the Marriott Hawaii properties as they all have something nice about them.
It depends on what you want. Ko Olina is secluded from Honolulu, by all means. Sometimes traffic can take you 45 min plus to get to Honolulu, which is Miami, by all comparisons. There are things to do on Oahu, but if you are into romantic get-aways where you can access waterfalls, volcanoes, etc., then I would recommend the big island at Waikoloa. True, there is no nightlife, but you are newly married, eh? The resort is nice, good pools, good service, a little low on the restaurant end there. Volcanoes park is a day-long adventure, then another day or two for the waterfalls on the east side (wet side). Diving is great there, as compared to Oahu, where boats are often overcrowded. There are other restaurants about a 5 minute walk from the hotel, a variety of them as well as a grocer and shopping.
Yes we were just there 3 weeks ago its beautiful, Try to get one of the cabana rooms seperate from the main building.They are right across from the fish ponds which makes it very quiet and private. There is shopping and preety good restaurants basically across the street. The hotel is great