We stayed here for a little under 5 weeks while renovating at home. The hosts were very accommodating and responded promptly to any concerns, even letting us charge our EV from the private parking spot. Be prepared for very narrow (as in one car at a time) and steep roads though.
The location is very close to public transportation, so the city center is only minutes away. Tourists will also appreciate the closeness to Ekebergskrenten.
The apartment is a typical basement apartment with new flooring and paint. The hot tub is nice! Crank the heat in winter though, the windows don't isolate too well.
We stayed here in winter, so we didn't use the outside area. I can imagine it's very nice on a summer evening though.