Pretty expensive (it's been a while so I can't remember). The food was good bordering excellent, the service was excellent, and the view and concept is of course the best part. I would recommend going at least once for a special occasion. I think I spent around 100 for dinner and drinks for two. Worth it for a special occasion especially when factoring in the uniqueness you can't get anywhere else in the city.
It's been several years since I have been there. I remember the food being very good. For two people you're probably looking at $200-$250 I think. They have a menu online with prices on there. It's a cool view at sunset and when it's a clear dark night.
On a clear night, cool season is a better view than summer. But its great for a view of city. Its terribly expensive and poor service, but I always take my out of town guest there for an after dinner coffee so they can enjoy the unique view of the city.