Just back from a 3 night stay at the Conrad Seoul and had a decent stay, although prob would not stay again.
Pros - easy 20 min taxi ride from Gimpo airport, connected to IFC mall, excellent river views, clean rooms, great blackout blinds
Cons - lots of construction in the area, heavy traffic (I only used taxis), breakfast quality was sub-par, poor bathroom construction fitment, front door/valet service unorganized (luggage not brought up until reminded, no order or control for taxi queue)
While the breakfast selection had a wide variety (western, korean, japanese, chinese), the quality was, in my opinion, poor. Food left under heat lamps for too long and turned stale, soft-boiled eggs that were actually hard-boiled (credit they did make them to order when I pointed it out), fruit that were not fresh and spoiling, warm coffee, etc. The executive lounge breakfast selection was much smaller than downstairs, although prob adequate for business travelers.