Im traveling alone and I stayed for 3 nights in sunflower hostel in a bedroom shared with 7 people. If you want to meet new young people I totally recommend this hostel! The environment is friendly and the location is also great. Negative points I would mention the cleanliness (specially the shared bathroom) and the noise (not bad if you want to party in berlin which was not my case...). Ah 5 points for the breakast (very good for 3 euros) and negative evaluation for the wifi which was not working properly.