I haven't used that company but I did the Carnival zipline tour in April. Your zipline tour sounds MUCH more exciting than Carnival's. Carnival's was the Bobsled and Zipline and was pretty "tame". The bobsled was about the same as a county fair roller coaster and the zipline, while fun, consisted of five short runs and a twenty foot repelling platform that was about the same as when you come down from the rock climbing wall.
Your tour is also $40 less than Carnival's.
Who doesn't care for ship's excursions.