We stayed at Nikolas's place for about a month and a half. The place was very clean which was great and in an awesome awesome neighborhood - 2 blocks from polk street so there is still a lot of great places to eat, but it is not noisy in the neighborhood. The view from the street outside the unit cannot really be beaten as you can see both coit tower and the bay bridge - its pretty fantastic.
The one downside of our stay was that there are hardly any windows in the unit. In the bedroom, you cannot tell whether is is 9 in the morning or 12 at night. It feels like you are underground most of the time. With that said - the unit is really nicely done and has great artificial lighting inside - and again very clean. So, I think this is a perfect place to stay for a short while, but perhaps not a month and a half. Also, great for a couple, but the futon is fine as well if people sleep separately.