My wife and I ate dinner here on our first night in Iceland. I went based on the recommendation of a friend. I also liked the look of the Icelandic sampler on the menu.
The restaurant is fancy, or fancier than I figured it would be, but it was also very comfortable. A nice place for a dinner date. The staff was friendly, especially the manager. The only (kinda) complaint is I asked for the Icelandic sampler with wine, but never got the wine. I did not get charged for it, and in the end it was probably better that I did not have wine, so no big deal.
The Icelandic sampler was great - a perfect chance to try a variety of Icelandic food. The whale was by far the best. The desserts were also great.
If you are looking for a nice dinner, this is the place to eat.