We had a lovely stay at Antonio's place! The location is great and the house is beautiful. Close to many areas by foot, bike or public transit. Our room was perfectly clean, the bed was very comfortable, and we appreciated having our own bathroom. We didn't use the shared spaces much (nor do others, it seems), but they are well-equipped, clean, and convenient. Our flight in to SF was delayed, but Antonio was flexible and accommodating.
There are a few aspects to consider, as mentioned in the listing/reviews. They were not concerning to us, but they might be to others. The house is shared with other travelers, so you will hear neighbors come and go. The cable car passes by the house regularly. The bedroom door does not lock from the inside or outside. We didn't travel with many valuables besides our wallet/passport and we kept those on us when out and about. They were not concerning to us, but they might be to others.
Overall, this is an affordable and high quality stay. We absolutely recommend it! Antonio is warm and friendly, full of recommendations to make the most of your stay in SF.