I (female, 37) had a very pleasant stay at Koy's. Just stayed there for two nights and spent the day for sightseeing in Oslo. Therefore, I just met Koy when I checked in. She is a very warming person! The house is located about a 20 min ride by Subway from downtown and is very quite and peaceful. Single ticket to downtown is 33 NKR. 10 minute walk to the station.
I had one of the rooms in the first floor, which was fine. Shared bathroom with toilet was at the same level and very clean. Showers are downstairs and are very clean. I haven't used the kitchen.
Overall a very pleasant stay! I can truly recommend this place.