Mark is an A++ host you never want to miss. He is extremely helpful and attentive in all the ways and respects your privacy at the same time. He himself is an amazing person, classic, artist-like, super good at cooking! He has the talent to make everyone in the room feel at home.
If you would like to talk and mingle with interesting people in town, Mark is my best recommodation. I will defintely come back to him when I am in SF.