Finished a 3 night stay here in June. Very much agreed with some of the consensus on this thread, but also disagree on others. The breakfast at Constans was amazing, simply the best breakfast buffet I've had ever. The mashed potatoes had truffle oil! As Platinum, I was given a one level upgrade from the base State room. The room was already very spacious with floor to ceiling windows facing north with stunning views. Service was 10/10, really all around felt like a pampered guest.

The downside is the location. I've stayed in Gangnam before, but Yeoksam is a bit different with its massive business skyscrapers and luxury apartments. Josun is 8-10 minutes walking from Yeoksam station, which is long by Seoul standards. And there are few local restaurants or places of interest nearby. We were much happier when we moved hotels halfway through our trip to Mapo, which was much more central and had hundreds of small restaurants to choose from. Between Myeongdong and Gangnam, I'd recommend Myeongdong for first-timers, especially since most tourist sites will be much farther from Yeoksam.