In this case, we used booking.com which at the time offered the best deal for this location and we stayed the 4th Night Free with a promotion from Hyatt. Even with sites offering exclusive Teacher Discounts this was just the best deal for us. Plus, at such an iconic location, it was very hard to pass up.
We had a great stay at the Hyatt, it was in a great location and we found it very easy to get around town. There was a trolley station right outside which made getting around very easy. There was also a muni-station and a BART station across the street.
Our favorite part of the Hyatt Regency was the incredible Lobby. It is a great place to relax and take pictures. We enjoyed our stay, we only wish that the hotel had a pool, however, there was so much to do, that we did not miss it.
Just keep in mind that In San Francisco there is a Destination Fee and we paid Hyatt a resort fee as well. Make sure that you find out about any fees that may come with your stay before you book. Especially if you are on a budget.
While we stayed at the Hyatt this time, I prefer to stay at Extended Stay hotels to avoid resort fees. I find that these hotels have the best overall experience for the price. Plus many offer free breakfast.