+1 on the ABTC card.
I've been beating my coworkers to the hotel by over an hour on arrival at ICN and beating them to the airline lounge by at least half an hour on exit. Although there is an arguement that waiting in long lines may be better than the KAL concourse lounge.

I have SES and ABTC. If I had to pick between the two I'd get the ABTC card.