A quick way to choose
Best all-round airport base: Hongdae
Choose it when you want direct AREX access without making the airport the only reason for the hotel location.
Best for KTX, large luggage or AREX Express: Seoul Station
Choose it when arrival, departure or onward rail travel is a major part of the trip.
Direct AREX without staying in Hongdae: Gongdeok
Choose it when airport convenience matters but you prefer a calmer evening base.
Best when central sightseeing matters more: Myeongdong
Choose it when palaces, shopping and central Seoul dominate the trip and the airport bus stops close to your actual hotel.
Your plans are mainly in Gangnam, Jamsil or Itaewon:
Do not move the whole stay west or north just to make one airport journey easier. The repeated trips during the rest of the holiday may cost you more time than you save on arrival day.