Price, cleanliness, polite/helpful staff.
For the price, it is really worth staying about 8km outside of Incheon. You save a lot even after the $15 taxi ride, $30 both ways.
Traveloka Sdn Bhd (Registration No. 201501003122), Level 14 Tower 2, Menara Kembar Bank Rakyat, 33 Jalan Rakyat Brickfields, 50470 Kuala Lumpur, Malaysia