This place is awesome! We had 4 people for most of our stay and no one had any complaints. The space was plenty big enough for all of us. The two bedrooms were plenty spacious, and the separate living room and kitchen allowed us all to have space to ourselves if we needed it. The kitchen and bathroom were well stocked with all the basics that you would need, and everything was spotless when we arrived.
The flat sits on the top of a steep hill on a very quiet street in the lovely Bernal Heights neighborhood. I never heard any neighbors nor any other city noises, and I always felt extremely safe in the neighborhood even walking around late at night. We even meet some of the neighbors and they were all extremely nice.
The flat is a quick 15-minute walk to the 24th Street Mission BART station which lets you get downtown in only a couple of minutes. It's also a 5-minute walk to Safeway, restaurants, bars, and Bernal Heights Park (the park is awesome for views of the city at sunset and is a must-see).
We always found a parking spot on the street, but you do need to be careful with what times you are allowed to park. The weekend is unlimited free parking but that changes during the week. We were able to fit a Ford EcoSport (same length as a Honda Fit) in the driveway with no room to spare so if you have anything other than a subcompact car, you are going to need to park on the street or in a garage somewhere in the city.
This place will be my first choice when I come to San Francisco in the future as both the space and Penny were a pleasure!