I was on the boat tours in Berlin before, but this one was absolutely the best of them all. The boats - Carola and Franziska - are smaller than other cruisers, which was a big plus for me, because they weren't so crowded. The seats were comfortable (not plastic!).
The trip was really relaxing and amusing. The crew was very nice and helpful. Our guide, Anna, was lovely and gave professional, but also funny commentary in both German and English. She made sure we all understood what she was telling us.
Also worth mentioning that the tour was cheaper than all of the rest nearby - it costs 12 euro, while the others charged 17 euro. Highly recommended!