I think it's a cool place to stay for a couple of days.
Keep in mind that it is quite far from the old town (about 40 min walking)
The rooms are very small and you will hear everything that happens in the hallway.
In April at least the top open deck wasn't working and the restaurant/bar closes at 11 pm. So since we were exploring Prague until nighttime we didn't have a chance to try out these facilities.
Altogether it is quite a fun place to stay if you're looking for a unique experience. But I'm guessing it would have been more fun in the summertime.
Also should add that all people working on the boat were super friendly and helpful. It was a real pleasure to come there every evening.