I stayed in one of the "hotel" cabins (that is, with a private bathroom) for five days for a business trip. The bed was comfortable, the room was clean, and the breakfast was good. Staying on a boat was fun, but not really different from staying in a very small low-cost hotel--I couldn't feel the boat move at any point. Overall it was an okay cubby to sleep in. I would stay there for a couple of days, but it's not ideal for a business stay.
Pros: Staying on a boat was entertaining. The location was extremely convenient to Sodermalm. I was attending an event at the Munchenbryggeriet, and it was about as close as it could be. The 24/7 reception staff was very helpful and polite, even at 3 AM--which is good, because they were having trouble with the door lock when I stayed, so they had to buzz me in. The main area (lobby/reception/breakfast/restaurant/bar) was suitable for sitting in and getting some work done (which is good, because the room is not), and the lounge area was comfortable and pleasantly appointed.
Cons: It's hard to convey just how small the cabin is. There was no place to unpack any clothing or toiletries, and I was tripping over my small suitcase. The bathroom is incredibly tiny and low-ceilinged, and showering took a bit of yoga. Although there was a fold-out table/desk in my cabin, there was no chair (nor room for one), so here was no real way to sit and work--that had to happen in the main area. Not ideal for a business trip or a longer stay.