We enjoyed our 1 week stay in this nice, centrally located appartment that is well equipped, and comfortable. We would certainly return.
Advice for travellers by public transport and with heavy luggage: If you walk from the GamlaStan Metro Station, the direct walking route takes about 8 min via roads with cobblestones. The walk from the closest bus station (1 stop from the bus stop at Slussen Metro Station, towards the center) is shorter and you will have to pull you luggage only over one road with cobblestones. The appartment is on the third floor without lift.
We had some small issues with a wrong entry code and a disruption of the internet service, but they were sorted out and did not affect our very positive experience overall.
Note that you will be in contact with the manager, not the owner, i.e. don’t expect any personal communication.