Stayed with our small children for two nights in early December. We were so warmly welcomed with the treasure box! And a beautiful Christmas tree and roaring fire that made me feel in the festive mood immediately. The staff are bend-over-backwards helpful, the double queen room was perfect, the Blue Mermaid restaurant was great for breakfast (gorgeous French toast) lunch and dinner! (Staff there super friendly too). Location is perfect for exploring the dockside area, right next to the cable car stop, and I highly recommend hiring bikes to cycle to Golden Gate Bridge.
We only had 36 hours but absolutely loved San Francisco and can't wait to return. And when we do it'll be to the Argonaut.