Dormyinn in Gangnam is a 5 star hotel for business travelers. It is not hotel for events or leisure, but it can be a hotel for a weekend-spa-cation.
I've traveled to Seoul a dozen times or so for work and play. Many of these trips were long 2 week to 2 month trips. And I've stayed at upwards of 30 hotels in Seoul. I've gone back to Dormyinn in Yeoksam, Gangnam-gu I think six times. It it my favourite hotel in Seoul when I'm staying alone. I've stayed at a couple Dormyinns in Japan too. The chain is one of my favourite for business travel. I think it should be good for solo travelers and couples too as I see many other guests of these types too.
The breakfast is a Japanese business style buffet with a Korean twist. The spa and sauna is quiet and private. The hotel has its own soaps and provides washcloths. There are smoking corners and ergonomic pillows. The front desk are multilingual and wear buttons showing the languages they speak. The hotel also serves late night ramen. The atmosphere is quiet and private just like the spa and the restaurant staff especially show excellent hospitality. There is no business facilities at this Dormyinn except for a public computer and printer. The laundry services are efficient and relative the Shilla cheap. What's most important is the consietency of all the services, even the food and rooms.
The hotel is located a 4 minute walk from two metro stations right in the center of Gangnam. There is a food street less than one minute walk away and more within 5 minutes walk. There is a gallery one block away. There are upscale restaurants as well as very local restaurants around the corner. It's a quiet hotel in a very lively area.