We've strung together video clips of our little adventure and added some music so that you can experience river boarding itself from the comfort of your armchair.
While in New Zealand, we went river boarding on the Kawarau River with Mad Dog River Boarding. It was fun, but not as scary as we were led to believe. Maybe it's terribly thrilling for some, but as surfers, we thought the rapids were...tame.
But, we did enjoy the scenery and the super-clear and clean water. Neil enjoyed the +20m rock jump at the end, and Berta enjoyed the hot showers (the glacier-fed river is really cold!). The staff were professional, and the activity well-run. We might some nice people doing the activity as well.
Overall, we'd recommend the activity. Of course, you must be able to swim and be comfortable in the water.