13 of us stayed on Olaf's boat for 3 nights for a stag do and our whole group was in agreement that being able to stay all together on the boat was a much better choice than staying in separate rooms/flats in the centre!
I was a bit nervous about how we'd all manage, especially with getting on board late at night (you do need someone to be sensible). However everything turned out fine and the boat itself was the perfect place for a group like ours.
The basics (beds, showers, kitchen) are all better than you may expect and of course everyone loved the beer tap. Getting around is also easier than I imagined, there's a bus/tram stop very close and you're in the centre in no time.
Lastly I should say Olaf did a great job looking after us, keeping the beer topped up and being there to help whenever we needed it, even on the middle of the night!