Having been to O'noir several times, I thoroughly enjoy the experience and bringing people along!
The food is decent, nothing exceptionally fancy of difficult, but it is fun doing it in complete darkness. I've heard of other places that just give you blindfolds, but I really like that you have no choice but total darkness here.
Not sure why they don't serve "Darkness friendly" food that is easier to eat than pasta or meat and potatoes, but that adds to the difficulty I guess.
Long story short, go to eat in total darkness, try the surprises, have fun.