I stayed at this Residence Inn for 6 weeks on business while traveling with a pet. It is directly on the Bay and next to the Caltrain tracks. It is also immediately adjacent to a Courtyard Inn and is about 10 minutes from downtown San Francisco.
If you face the Bay, the rooms are quiet and the view is simply breathtaking in the mornings. There is a big walking trail around the Bay and a great place to run, bike, etc. Although this hotel is five minutes from SFO, the planes do not fly overhead and there is no noise. However, if you are on the side of the hotel facing the train tracks, I think there would be some train noise. I never experienced it personally, however.
They have a shuttle going to the airport every 20 minutes, where you can catch BART into the city. You can also get a shuttle to the Caltrain station 5 minutes away, but it requires a special request.
They have the standard Marriott Residence Inn amenities -- hot breakfast, mini-mart with snacks and alcohol, comfortable beds, full kitchen, multi-room suites with 2 TVs, good selection of CATV, a desk, etc. This place is very crowded on weekends with travelers, but mainly business folks during the week. The parking can be tight on the weekends, but I was always able to find a spot. This is a huge property and it can be a hike from your room to the breakfast area.
There is a Courtyard next door that has a restaurant and you can use their workout facilities and pool, which are slightly nicer than the ones at the Residence Inn.
My only complaint would be the housekeeping could step it up a notch and the water pressure was sometimes a bit low. But other than that, I highly recommend this place and would not hesitate to stay again for either one night or a long-term stay.