upscale japanese in orange county?
Bluefin is a very good choice for omakase with cooked foods and sushi, but the room is a little cramped, so not very intimate.
Hamamori is somewhat overpriced, but the room is nicer, though somewhat cold and sterile. Food is good but expensive.
Kitayama I have not been to in about three years, but yeah, it is an old warhorse on its last legs. It does have small secluded booths, however.
I personally would pick Bluefin for the food.