Stayed for 4 nights while attending recent Stanford Homecoming. It was a good price for the Palo Alto / Menlo Park area, and the rooms were clean, staff were friendly. I believe guests need to have a Stanford affiliation / reason to stay at the Guest House, e.g., attending conferences, or families checking out the campus for their kids college applications.
What I liked about Stanford Guest House:
1) Convenient location - Although it's not near the main campus or any major facilities, the Stanford Guest House is served by 2 different shuttles: (a) The Stanford University Marguerite shuttle (the SLAC loop line) which runs on weekdays, and takes about 15 mins to get to Hoover Tower, and (b) the Guest House's own shuttle, which you can reserve to take you to / from different parts of the University campus and which runs only on the hour.
2) Clean rooms
3) Strong wifi - I stayed in room 123 and had no problems with the wifi at all, which runs on the Stanford Guest network, which covers most of the Stanford Campus too.
4) Secure. Because it shares the same entrance as SLAC, there is 24-hour security that checks who comes in and out.
5) Self-serve laundry available (2 washers, 2 dryers). $1.50 per wash, $1.25 per drying cycle as at Oct 2013.
6) "Peet's Coffee" self-serve machine available 24-hours for free. I don't drink coffee, but my son loved the hot-chocolate available from the machine.
7) Decent continental breakfast included with the room.
8) Plentiful parking at the Guest House and around SLAC.
What I would have preferred:
a) Bigger rooms. Our queen room was kind of small, with just enough space beside the bed to lay out our suit case, and not much else.
b) Apple juice that didn't taste so watered down at the breakfasts.
c) Larger refrigerators. The Guest House has 2 shared mini-fridges in the common pantry, where guests could label and store their items. They were always full.
d) More flexible timing for the Guest House shuttle. Instead of only running on the hour, if there were no other bookings, they should consider running the shuttle at the convenience of the guests.
I would stay there again when I return to visit Stanford.