We stayed at the SPG Design Glad hotel in-between Seoul and both airports.
GLAD Hotel SPG
This was perfect because the location is in-between both Seoul, Incheon Airport and Gimpo airport.
The metro is in front of the hotel, takes you between Seoul and the airport lines (AREX).
I loved the super quick metro trains - they were inexpensive to get around, clean and safe!
The hotel staff was super and the dining in the hotel was excellent!
We received bonus points, free bottle waters, late checkout, and room upgrade (in Asian standards) for 175,000 WON ($165) per night.