Trip.com had a mismatch with this booking and I stayed at Hyoi Stay Busan Songdo. It's the same hotel as they said, just a different name. It's also the same building and room type was identical. So my review is for Hyoi Stay.
Great hotel, new, very clean room with a washing machine and a dryer. Location is also great, view from the room was beautiful. Hotel is like airbnb, room also had a kitchen and a balcony. Very helpful and nice manager met me near entrance of the building to help find the office on 3rd floor to check-in.
Now, if you don't have a car and don't use taxi, be careful as the walk from the bus stop is going downhill and if you have a heavy bag coming back up can be hard. Even with this it's only 10 minutes walk from bus stop.
Overall 5/5 loved it, would gladly stay again.