I stayed with Yuca for 3 nights in September 2014. I chose his listing for its location, separate entrance, private bathroom, spaciousness and overall tidiness. His description and pictures were very accurate, so there were absolutely no unpleasant surprises when I arrived. The direct access to his private patio with views of the city was a fantastic bonus. Also, the bed's mattress and linens were incredibly comfortable, in contrast to the futons and budget mattresses I saw in other listings.
Although I've stayed in AirBnB spaces many times prior, this was my first experience cohabitating with the host during my visit. Yuca made it very easy and hassle-free. As he notes in his photos and description, the guestroom is separated from the rest of his house with an L-shaped staircase and curtain, which I personally felt offered sufficient privacy. Yuca himself is a very charismatic and flexible host. He's curious about his guests and eager to offer local guidance, but can also respect if they'd rather keep to themselves. He has a lot of experience hosting guests, so can anticipate their needs and questions.
In sum, I had a wonderful time staying with Yuca and would emphatically recommend him to anyone seeking a serene, private and clean place that's accessible to the Castro and MUNI.