They have so many cocktails to choose! And each of them are really really good, which makes me come back again and again, wagering to finish the whole cocktail list. To mention a few, tiramisu (cocktail) is literally what it tastes like and very special, the grasshopper is refreshing, the lychee is sweet, and the champagne selection is also good. I usually go with the tempura plate to share with friends.
Opus is definitely the best lounge bar in Madison!