I recently got the chance to spend a night a the Hyatt last week and it was the best experience. The location is amazing- a few steps away from BART, the Ferry Building, Embarcadero Center, and a few blocks from Union Square. Easy access to Fisherman's wharf and other sites too! The concierge is knowledgeable and helpful, and staff is very friendly.
I also have to say that the rooms here are top notch, equipped with mini-fridge, nice bathrooms, and high quality bedding with pillow top mattresses with tons of down pillows. The bed was the seriously the highlight of my week!