Had lunch there. It's not the Onyx, but The food was very good. beside, you really can't complain when you pay 1390 HUF for 3 dishes and a lemonade. I also ordered coffe and wine. the wine list is huge, and has wide range of prices. the coffe was good, and come with small glass of water (not sparkling for some reason), and few candies.
The place has a great design, and suitable for romantic dinner ot business meeting as well.