I had a two night stay at Elia Ermou and it was an incredible option in a great location.
It's located on Ermou, the shopping district for Athens filled with a mix of stores - H&M, Zara, Mango, Funky Buddha, Korres, the list goes on. It's also a quick walk to the beautiful Holy Metropolitan Church of the Annunciation to the Virgin Mary, worth peeking inside to see the Greco-Byzantine style.
There are tons of restaurants, bakeries, cafes, etc. Το Χρυσό Στάχυ is right next door and great spot to pick up some pastries.
We did a walking tour of Acropolis while in town and the hotel was a quick 15m to our meeting spot and afterwards, a quick 20m walk through Plaka back to hotel. It felt very centrally situated.
Our room was quite large compared to what I'm used to in other European cities. The bathroom placement wasn't the best - it's sort of semi-private so could be awkward if traveling with folks you are not too close to. Room and all spaces were very clean. Felt very modern.
The rooftop bar / restaurant was incredible. We had a lovely view of the Acropolis. We had dinner there the same night we visited Acropolis so a great way to cap the day.