I stay at the Grand Hyatt Seoul whenever I'm there for business, typically twice a year for 2-3 days. I look forward to staying here when planning my Korea trips. Delivers very well on the Grand Hyatt brand on all the notes - the grandiose lobbies, the great restaurants, the good service - but still manages to be a warm welcoming and comfortable experience. There is an abundant use of wood in the interior, and the rooms themselves are very clean and simple, almost minimalist (in the positive sense of the word). The glass desk runs across the width of the room, in front of the full size window that offer a great view from atop Mt Namsan whichever direction your facing - makes a good place to get stuff done. The restaurants as mentioned are great (and flexible - the Japanese restaurant on two occasions agreed to open and let me be seated at 11:30, a half-hour before their official lunchtime opening in order to accommodate my packed schedule), and the room service is not bad either.

The only potential downside might be a slightly inconvenient location, being right on top of a hill, though i'd never had to really wait for a taxi (though sometimes in the evening when returning there is a decently sized queue from the dinner/partiers at JJ's leaving). I believe there is a bus that takes you down to the tourist / expat ghetto Itewon and the subway stop there, but I've never taken it, as I'm usually there just for business.

I spent two nights in the Grand Hyatt while on business to Seoul. I found the hotel itself to be very nice. They have great views of the city. The lobby bar was great with large windows and nice views. The staff were very friendly and helpful. There were a number of restaurants and the health club was well appointed. The one minor complaint was the cost of accessing the internet. When staying at a high level hotel and on the club floor I would expect free access to internet. I don't think a hotel should rate 5 stars in this day and age if they are charging for internet service.

Located at the top of a hill wth great views of the Han River, the Grand Hyatt Seoul is a good choice for leisure or business travelers. Rooms are comfortable, but not very large. Restaurants are good and the lounge at night is terrific for a drink and view of the city.

A beautiful hotel: located on top of a hill, overviewing Seoul, a very cosy atmosphere once you walk in, comfortable rooms....Only one little drop of bitterness: if you like to walk around, you can only reach Itaewon with its bars and restaurants and small shops, but there is no walking distance to the main shopping districts downtown, so you have to rely on the shuttle service, or taxi,..
Very special: we stayed there during a December weekend, so we could enjoy marvellous Christmas decorations inside and outside, not to forget the ice rink in the garden area with views across town while skating!