My Korean food experience is limited to Madison and Milwaukee, but as far as I've seen, New Seoul is excellent. Bibimbap is good, my friend raves about the Pork Bokum as being just about his favorite thing ever, so long as you shouldn't care about how your breath smells afterwards, and their Dok Mandu Gook (rice cake dumpling soup) is simply delicious. I would also recommend their vegetable Korean pancakes (not sure of the Korean term for those) with soy sauce as an appetizer.
There are two Korean restaurants in Madison that I know about, and New Seoul seems to be the one that Koreans prefer, which says something to me about authenticity. I would highly recommend New Seoul for anyone looking to expand their culinary horizons, or who's just a fan of Korean food.