Great for backpackers
This place is new and so the facilities are clean and the rooms are air conditioned and very comfortable. The girl in charge, Sophie, was very friendly and even took us around to some of the bars and clubs on a Saturday night after I asked her to. The coolest part is a rooftop bar with great views of the Acropolis and surrounding Athens.
If you've never been to Athens, you should be warned that the streets/sidewalks aren't looked after in certain places, and there is graffiti all over the place. If you're used to the glamor of places like Madrid and Paris, Athens can be a shock at first but Athenstyle is definitely one of the nicer/cleaner hostels you'll find.