We've had dinner twice at the Wave (most recently about 10 days ago). At Kona, we had lunch twice (including Sunday) and dinner three times.
We really like the food at the Wave. DH had steak and said it was excellent. I had the fish--and really liked it. Desserts are good. It's quiet but also relaxed. Our server was very, very good, better actually than our servers at either Citricos or Narcoossee's.
We like Kona but think the quality there has really slipped, and in fact, we left it off our ADR list for our recent trip (though it worked out for lunch as we were on the way to the airport). It's noisy, as others have said, and the dining room is very crowded. Food was good in 2006, slightly less good in 2007, and then very disappointing in 2008. DH in particular does not like it.
One other perk with the Wave is that the tables are spaced nicely, so you will not be on top of other diners.
In December, we'll be returning to the Wave, but not Kona unless we stop in for a quick lunch.