I've stayed at both the Intercons in Seoul several times. The Intercon-Coex is newer but very wanky about Ambassador Club upgrades ... they'll give you a room on a high floor (in spite of having booked that anyway) and consider that your upgrade. The Grand Intercontinental bumps you up to a Junior Suite ... I'd booked a club room so had lounge access ... fantastic ... and all the staff knew my name on sight ... impressive