Don't bank on it
My husband I used our free Marriott certificate to stay at this hotel for Saturday night and overall found it not be a hotel we would return to this hotel again. Let's break it down:
Plus: We did arrive early on Saturday and were able to check in early (before noon).
Minus: Staff at check in were kinda snotting and used a unfriendly tone.
Minus: Parking is $33
Plus: Cab ride from the airport with tip is only $15
Plus: Can walk to the gaslamp, Horton Plaza, the transit lines and Amtrak, and even the Seaport Village
Minus: Loud hotel room; lots of street noise; lots of noise from the evalator and hallways
Minus: Breakfast was AWFUL. We both had a the buffet - cold food and never were offered a refill on coffee until my husband went and help himself. (It was not busy). I will walk to Subway instead of ever eating there again. 
Minus: The room was boring and rough condition. We had a king bed, one chair and office chair. The chair needed replacing.
Plus: Comfortable bed
I had stayed here once before and do find it to be in a good location; but will avoid this hotel in the future. I won't even waste my free night on it!