I have flown through Seoul several times this year. I was looking forward to ICN.

Enormous improvement of course. I especially liked the fact they added a transit hotel (actually 2 of them). There is one in the west terminal and one in the east.

I didn't appreciate hassling with customs at SEL and then getting in a hotel van for a minimum of 20 minutes each way. It wasted so much time.

The transit hotel is a two minute walk from the gate and it is a Starwood property. The cost only 33.00 USD for 6 hours