Jessica and Mark offer a very nice apartment which I recommend. I really appreciated the responsiveness of the hosts, the easy self check-in, the central location close to 16th Street BART station and great restaurants, the cleanliness, having heating in the room (not a given in SF) and the well equipped kitchen. In the morning you get very nice sunlight in the room. Downside of the central location in the Mission is that you will pass by a somewhat rough strip on 16th St on your way to and from public transport, but I never felt unsafe. Also be aware that you will share one full bathroom (toilet + shower) and one separate guest bathroom (just toilet) with up to three other people, but we had no problems at all during my 1-month long stay. In total, 5 stars!