I had a great experience at Martha's place. She and her family are very welcoming and easy to be around and it seems she enjoys being social with her guests but it's no problem if you want to do your own thing and just come and go. The room is very comfortable and quiet- I slept very well.
The home is located in a very convenient and safe part of town with a delicious bakery right around the corner. I would most certainly rebook the next time I'm in SF!