I highly recommend Denny. He was great. I had a great tour of Seoul during my layover. He picked me up at my airport hotel and then we saw major attractions like the change of guards at the Royal Palace, but also some not so touristy places like local markets or the riverbanks. The tour was based on his recommendations and personalized. I enjoyed it and learned a lot. He took me a very nice local restaurant with great food for lunch and made sure that my diet restrictions were followed. At the end of the day, he dropped me off at my hotel. A completely worry free tour. Again highly recommend.