Positives: Very helpful staff (Juan and Alessandro), very close to the Alhambra, lovely Realejo neighborhood, adequately-spaced rooms, well-lit (daylight) and colorful rooms, easy to sit in the living room and make new friends. Negatives (room for improvement!): Limited choices for breakfast, very shaky/noisy/scary bunk-beds, no ladder for all the upper bank beds, average size of bath towel, no individual light for the beds.
As other people have said, the hostel staff are great and will give you information about anything you need. The location of the hostel is ideal for exploring both sides of the old town, however the very noisy (drunk and singing) tourists might keep you awake in the (dorm) rooms facing the main street. The 7-person female dorm is spacious enough however the bad smell coming from all the sewage pipes in the ensuite bathroom is quite unbearable (even though the bathroom fixtures are new).
High points: Feels like entering a friend's relaxing apartment. Spacious main bathroom (cool curtain!). Easy to socialize with others. Marius (owner) is making an effort to get to know his guests. The 6-bed dorm is spacious enough, with bed-side lights and cloth hangers. Low points: The 6-bed dorm is next to the living room (if people talk loudly at night you will hear them) and has lots of light (beware if you like dark bedrooms!). Small elevator in the building. The main bathtub gets clogged.
Compared to other Athenian hostels, this one is the newest and the best! Stayed in 6-bed mixed dorm with 2 others. High points: Relaxing and colorful common room, welcoming staff, great breakfast, rooftop view of Acropolis, centrally located, good value for money. Low points: No tissue paper next to the bathroom sinks (yes, this is important!), the 6-bed mixed room can get crammed (and smelly!) when full, must be cautious in the surrounding streets late at night, the toilet pipes are smelly.
I have stayed in other hostels in Europe that were significantly better value-for-money than this one, much cleaner and with better amenities. The 4-bed female dorm I stayed in was not clean. There was garbage on the floor, very small garbage can, mold in the bathroom and the water smelled too much of chlorine (I chose to wash my hair at a nearby hair salon). The shower space is so tiny, it can be claustrophobic. I was given a medium-sized towel for 2 euros (luckily I had other towels with me).
I landed in Vienna having very strong doubts about whether I like the city.... until I entered myMOjOvie....that's when I said "yeah, baby!!!" :)) Great place to stay at, close to transportation options to get to the center (tram, bus, on foot), great host (Julia) that gives excellent ideas on where to go and what to see.