We were interested in the Active Cruise that was offered. We went from Budapest to Linz and added Prague. I'd say overall the cruise was awesome. The food was great, the ship was great, our cabin was nice, comfortable bed, and the crew were great. Also, all of the activities were very well organized. I'd say our only room for improvement was the following:
1) The 2 hour briefings were way too long. It is hard to focus beyond 30 minutes.
2) We would have loved to have a little more time just relaxing on the boat. That was probably our own fault for signing up for too many things.