Let me say upfront that this place has been a fantastic deal for me.
I needed an extended stay (for 45 days) in central Athens and found this place on Air BnB. It is a fully furnished studio. Its kitchen has a fridge, stove and all essentials for cooking. In the living room, there is one big and another smaller bed. It is ideal for a single person, although two people would also be comfortable. There are bunch of clean linens and towels. There is also a washing machine, you can use anytime. The balcony is sweet: I had virtually all my home meals in there. There is unlimited free internet.
The location is perfect. Pangrati is a decent neighborhood, with numerous coffee shops and restaurants all around. This place is 15-30 minutes walking distance to all major attractions, like Acropolis, Monastiraki, National Gardens, Licavettus and Syntagma. Metro station (Evangelismos) is 10 min walk, and within 2 minutes walking distance are bus stops. Just one block away, there is a park, where I run and exersided time to time.
The owner is a very kind person. Speak fluent English and does not bother you.
All in all, I had been quite content about my stay here. If you are not looking for luxury, but a clean, decent, convenient and fairly inexpensive place to stay, I'd comfortably say go for this one.