I stayed at Ibis Myeongdong with my family (husband and 4y.o son)
The standard room is small but enough for 3 of us.
Very convenient location. Lotte mall just across the hotel. Many good restaurants and shops surround (which i love).
You can take limousine bus from the airport and get off in front of the hotel. Very useful because taxi from airport to myeongdong quite expensive.
You can also use the shuttle facility to go to major tourist attraction like gyeobokgung palace, invading, etc.