We enjoyed this evening show. Booked it with the travel agency that is caddy-corner from the McDonalds. Rony from the travel agency speaks great English. We arranged several tours through her.
This is activity that we would put in the category of doing while you have an extended time period, more than 3 days, in Yangshuo. A little pricey at 180 yuan; but if you have the time go ahead and do it. It was arranged by the same person who did the Beijing Olympic final night extravaganza.