The night tour is awesome - not only is it a little more eerie, but on top of getting headsets for the audio tour (just like the day tours) there are several park rangers scattered about who do different presentations and can answer questions. We saw several mini films and heard lots of tales from the Rangers. This was an added extra that was not available for the day tours at the time we went. We did the night tour a few years ago and it was well worth the extra couple of bucks. The view of SFO at night from the island is spectacular.