Positive: Perfect location, just a few minutes away from the entrance to Acropolis. Plaka and city garden is close. 10 minutes from Syntagma and bus stop from the airport. Easy 24h check in and check out. Generally the place has everything you need to spend a few days.
Negative: There was no cold water in the tap in the bathroom as there was a hole in the hose and water was simply turned off (so the owner should have known about the issue). I contacted the owner, got quick reply. But it was not fixed and I couldn't use it for 3 days!!! It means that the owner doesn't care. The bathroom is tiny. There were some noisy construction works during the day.
Conclusion: It could be a 5 star rating, but I can give only 2.