We stayed here for a week and although visit Amsterdam regularly, this was the first visit here. Great working building with lots going on.
The rooms are quirky. It had just been a very hot period and the heat was clearly still in the building, the room was hot without any air conditioning, only a (really) basic fan. Sleeping with the window open wasn't an option, there's a lot of outside noise, especially around the back of the building.
The room was somewhat let down by a lack of general maintenance, broken blind (no daylight for the whole stay), no descaling of shower head (more water on the walls than on my head).
The breakfast is basic but fine. It should however be pitched at around 9 euros for what you get (compared to other hotels) instead of 12.50 euros. The breakfast staff are really nice. Not much is replenished the last hour so don't wait till the lat minute. Having said that, there are loads of other places to have breakfast within a 2 minute walk.
Other than checking in, we had very little to do with the reception staff, the guys we saw were friendly. The girl doing evenings shifts seemed away with the fairies most of the time and we were always met with a blank expression - it was actually quite funny.
The cafe is great for evenings drinks too, very reasonable prices. Partly because it not only caters for hotel guests but also the music companies and studios etc which are also in the same building.
All in all, I would happily stay here again.