I stayed at Cocomama for 4 nights recently, and I can't speak highly enough of this place. The staff are brilliant and love to socialise with their guests and organise lots of cool activities. I also met lots of interesting travellers and particularly loved the communal / lounge area and the camaraderie between travellers. It is a little more expensive than other hostels but it is worth every penny and more. The rooms are very spacious with high ceilings and massive, comfy bunk beds. They are all themed. I stayed in the windmill room, but there are plenty of others too. The hostel cat Joop was also a little star. I felt sad to leave and will definitely be booking here again when I return to Amsterdam!