We decided to pay the extra 100 quai and go up to the 91st floor outdoor observation deck. I was disappointed to find that the outer wall was so tall, preventing anyone much shorter than 5'10" seeing over it. Neil had a good view, but I had to hop around to see anything. We walked the whole perimeter of the deck, and found a nice little movie theater with a short film about the construction of Taipei 101. That made the extra money worth it. It was very interesting.