The San Mateo Marriott property itself is great. I believe many (if not all) rooms are suites are junior suites. It has a nice lounge for breakfast.
In terms of location, San Mateo itself is pretty boring. The hotel does offer a free shuttle to SFO though, and from there you can take BART to San Francisco.
There is free wi-fi in the lobby, and elite members also get free wi-fi in the room.