Went on this with the family. We all loved it. Offers a different experience. Get to see the Gold Coast On land and in water in the one vessel. As the kids said 'pretty cool'.
I think these duck rides are aimed more for the kids and international tourists. We had a good time but it was a pricey experience to just stare at streets. Entering the water was fun & the kids enjoyed driving the boat. Luckily we had a buy 1 get 1 free through our accommodation as i would've been disappointed to pay full price. This duck does the same tour as all the others, we even saw one of the opposition broken down. Staff were friendly but it got a bit annoying that they constantly picked on their opposition, even the duck voice recording was teasing them.
My family & I had a blast on the Aquaduck while on holidays in Surfers Paradise recently. We got to see a lot of the Gold Coast's streets, beaches & landmarks both on land (driving through the streets) and on water (diving into the river up near Seaworld). The kids had a great time as they even had a chance to drive the duck while on the river. Plus they got a certificate afterwards. I highly recommend Aquaduck to everyone.
Approximate cost: $35
Sounds like lots of fun. Might give it a whirl