I really liked the hostel. Its location makes it easy to reach all the main attractions of Istanbul easily. The staff also was very helpful and tried to answer all your questions as good as possible.
Riva hostel Pula is a grat hostel even if its a new one. The location of the hostel is great, just by the sea and everything is in walking distance (sightseeing, stores, bares, bus station, etc). The staff is really friendly and will help you plan your stay in Pula or tell you the best places to go. The kitchen and the common room are great to get to know the other travellers. The only downside is that you have to leave the hostel when they are cleaning up.
Hostel Ana in Rijeka was not what we expected. The included breakfast had to be paid extra, our 8-bed-dorm hostel about 11 people and cleaning of the bathroom was seemingly not a priority. Apart of that it was located next to the city centre, the bus station, etc., there are stores, internet cafes and restaurants nearby.
Hostel Ana has a great atmosphere. We were immediately welcomed and had a great time :)
The rooms are clean and nicely furnished. We booked a 2-beds-room and had really comfortable beds, a desk, chairs and an amazing view of Dubrovniks port. You get your own keys so you can get in and out as you wish. Its not really in the centre of Dubrovnik, but there is a bus station nearby or you can walk ( ca. 20 min). All in all we really enjoyed our stay there. Insider Tip: The Krile's house is a little bit difficult to find, because the street consists of steps.