I very much enjoyed my stay at Bill and Helena's place. The location is about as good as it gets in Athens. 5 minutes walk to the Acropolis museum and the pedestrianized historical center and 2 minutes walk to the nearest metro station. Also 5 minutes walk from Philopappou Hill, which is a green enclave in the middle of the city with views to the Acropolis and the Aegean sea and a great daily hike/workout. (Make sure you visit during your stay. I did and I was hooked and went up and down every day after that.)
The place itself is lovely and very clean. I only used one of the beds and it was very comfy with clean and good quality sheets and comforter. The kitchen is well equipped with everything someone would need to cook. Bill and Helena left coffee, tea, honey and a few other basic amenities. Bathroom is fully functional, shower has excellent pressure. Wi-fi works perfect and with nice speed.
The hosts have left several books and leaflets with information about Athens and they were available to answer questions quickly via text or phone.
Overall, this continues to be an excellent space for my trips to Athens. I will stay again next time!