Sofi's place was nice and cozy. The space was clean and tastefully decorated. The location was great and allowed us quick and easy access to the main street in Gamla Stan. The flat feels very safe as there are two levels of passcode protected doors as well as a key for the flat door. For those who have difficulty climbing stairs the flat is located on the 2nd level and there is no lift access.
At night it can be a little noisy as there is a bar directly below the flat on the ground floor. If you close the window you don't really hear the noise too much. That can be a problem if it is hot outside as there is no air conditioning. Most of the time the weather is cool enough so this won't be a big problem. On weekdays it is fairly quiet.
Overall I recommend Sofi's flat to anyone who is looking for a place to stay in Gamla Stan.