The apartment is a nice size for a studio and has everything you'd need for a short city stay.
The downside is that that the only windows open onto the internal courtyard, and noise from that courtyard is amplified. There is a continuous low level noise of some sort (like a large extractor fan), which I found annoying (but others have not commented on this so perhaps it is just me!). I think this would be fine in colder months, but not ideal if you want to have the windows open during warmer weather.
Slussen is an easy transport hub, but with the current construction works is not the nicest part of town to stay in. Nicol did warn me about this, and I'm sure does the same for other travellers!