NOT for a family trip!
Our family has relied on the Marriott hotel and vacation club for more than a decade to always provide quality service and SO many wonderful family vacations and weekends! This is the FIRST negative review I've given a Marriott. 
This is NOT a family friendly hotel unless your family is traveling with one of you on business and someone else is footing the bill. It is a great hotel for business or event specific stays (i.e. weddings) and the hotel lobby/entrance, etc. is a beautiful. If you are only going to try and see Fisherman's Wharf, ride a cable car, see the edge of Chinatown... this hotel might work for you. If you want to see the rest of San Francisco and you're not driving or planning on taking a Taxi, it is NOT centrally located to anything!! It took two buses and a cable car to get back from Golden Gate Park. You have to get yourself into the central district to get a MUNI pass. (Taxi is about $9 w/no tip) 
The rooms are unbelievably small and are not appropriate for a family of 4 or more. Few rooms have a view of anything but the roof. We arrived a few minutes prior to check-in time. It took awhile for them to find us a double bed (what we reserved) and asked my son and I if we could share a KING?! (I'm his mom and he's a teen?!) It was also a problem that my husband made the reservation and wasn't staying with us?! Even though I provided them with MY Marriott reward card for all payment during our stay?! Really?! NEVER heard that before?! What is this 1954?! 
There is only one restaurant on location. It is beautiful. However, it took over an hour and a half for my son and I to be seated and served breakfast. Two mornings in a row. It was over $50. For pancakes and coffee. There were so few staff available it left everyone looking stranded with their breakfast dishes and huge bills. Also, there were two receptions hosted in the restaurant/lounge areas of the hotel. We just saw this passing by, but there are no walls, so if there is an event it bleeds over into the dining area. A tad uncomfortable, especially if you have children who need to eat and just did SF all day! I saw one family absolutely miserable and trying to enjoy a dinner (definitely over $100) in a room filled with over 60+standing strangers enjoying cocktails and hors d' oeuvres! Yikes! 
Lastly, the area around the hotel is filled with great restaurants! BUT, be prepared to pay more than $28 per entree. If you walk about three blocks in either direction, you'll find more affordable stuff. 
If you have a family, choose a Marriott closer to public transport or with cheaper parking rates.