Mary's place is great. walk-up in a safe building. my room was top floor and had wifi issues. But Mary fixed it right away with a new router, awesome. Thanks Mary!.
The place is up the hill and close to Moscone center where I needed to go 4 days in a row; about 10 minute walk.
A very nice touch is access to the shared kitchen on the second floor with several breakfast food items for the guests (milk, eggs, toast, nutella etc).
I would definitely stay again. ah yes, and one thing about noise that other people wrote about also. It is a bit noisy, you hear cars, but it is smack middle in the city for where you need to go and it makes sense. I slept very well nonetheless in the very comfy bed.