This hotel is superbly located for the archeological sites - almost adjacent to Hadrian's Library, a few minutes walk from the Roman Forum, and 7 minutes from the Agora. The best way to reach the hotel from the Airport, is the the underground train. It runs right from the airport to the Monastiraki station, about 5 minutes walk from the hotel. The journey takes 45 minutes, and the train runs every 30 minutes. It was spotlessly clean, and very pleasant. There is a €10 family ticket which meant we paid about £3 to transfer from airport to Hotel ! The only tiny difficulty with the underground is arriving at Monastiraki station - like some London stations, there are several exits from the station. Make sure you use the right one before heading off to the Hotel.
From the outside, the hotel did not resemble the pictures I had seen - we almost walked past the entrance! However, inside it was clean, light, and the chap on reception was very polite, spoke excellent english, and insisted on carrying our bags up the 4 steps into reception. We had pre-booked a room with a view of the Acropolis (€15 per night) and so we were on the 3rd floor. The room was failrly small - but clean, and the bathroom was better than the one from the London airport hotel we had stayed in the previous night. The hot water was plentiful, and temperature was constant. We had a mini-bath with shower over, which was fine. There was one bar for hanging clothes - about 10 hangers. The e-safe was a safety deposit box with a number pad allowing the user to select a 4 digit number - very good - and meant no key to carry. The room had a kettle for making coffee & tea, and the usual mini-bar. From the floor plan, it appeared the rooms were all different shape and size.
Now for the bad news - noise. Athens is not a quiet city at night - from the groups of barking dogs, noisy mopeds, and garbage collectors (from 4:30 am!) there was plenty of noise at night. The 3rd floor is the highest that has rooms - but above us was the very nice rooftop breakfast area. Breakfast is served from 06:30 to 09:30, and so the staff were setting up from 05:30. That meant moving chairs and trolleys across the tlle floor immediately above our heads. More noise. Therefore, we would definitely recommend earplugs. I would also say that the Acropolis view isn't worth it. As you can see from the attached photo, the view is slightly blocked by a palm tree (we were in room 306, there were 3 other rooms facing the Acropolis on our floor), but the view from the rooftop at beakfast was much better. With hindsight, we would have had a lower room, which were larger, and possibly quieter as we would have not heard the breakfast noise.
Rooms in the hotel either face the Acropolis, or face the road. The road is very small, but the front of the hotel faces a pretty square, filled with trees and restaurants. We didn't experience any noise from them, but it's possible. Again, earplugs would be useful.
Breakfast was OK. The staff brought a glass of freshly squeezed orange juice, and the rest was self service - cereals, bread, honey, jam/marmalde, yoghurt, fruit, cheese, cold meat, as well as bacon, and fried eggs, coffee and water.
There are lots of restaurants about 3mins walk up Adrianou street. All serving standard tourist food, but worth exploring.