The hostel is nice and clean, and with a great location. The 3 stars is due to the poor service we got, when we had to switch apartment because there was no heat in any of the radiators (we spend the first night fully clothed and with 2 duvets).
Long story short: we agreed to move to another hotel, first a double room that were simply to small, and at last (due to 1 nice receptionist), an apartment which was not initially suggested since it was more expensive. The space and at least a fridge was important to us because we have a small baby and spend all evenings in. But the fight continued - we had to pay for breakfast again, because it was more expensive at the new hotel (same owner). We tried to meet them half way and asked them for a breakfastplate so they could reconcile the food and the money, but that was not an option either. Somehow, their mistake (an apartment without heat) became our job to fix. We lost an afternoon waiting for them to either refund the pricedifference from apartment to a room or find us an apartment. I've worked in the hotel business myself: if there is something unacceptable about the room (heat is quite essential in the middle of october), you switch the customer to an equivalent room or a nicer room if an equivalent is not available. The price difference is your problem, not the customer. You promised an apartment and breakfast, and we payed for it and expecet to get just that. I have never felt so unwelcome in such nice surroundings.