I stayed at Jason's for a week for a conference downtown. It was very conveniently located, 5mn from the BART, close to all the action in the Mission yet quiet. A few harmless homeless people around, that's unavoidable in SF. The room was great, clean, exactly as on the pictures. The bed was very good - slept like a baby.
Jason was very easy to deal with, quick in responding, and a great host. There were other people sharing the house, but there was ample room for everyone, with two bathrooms and a large kitchen with everything. Overall, a great stay - definitely recommended.