We stayed here for 9 days in September. It was an ok experience, but I would advice to have a room away from the main street, which is right outside. It is very loud when trying to sleep.
It is a small Hotel, with nice staff and pretty good food. Pool area is small but good. Gym is very small, almost for 2 people maximum.
The rooms are clean, but small, and beds are great.
We had a visiting cockroach in the bathroom in the rooftop suite. It was the largest I have seen in my life. We showed it to reception, and they offered us free breakfast for two days which I thought was very cheap of them.
For short stay, it is a decent hotel, but for longer I believe many other hotels will give a better total experience then this Hotel in Glyfada.
And - they dont have Beach towels. Which is unfortunate.