We booked ABA Boutique Apartments for a 5 night trip to Athens and would definitely recommend. The property is lovely inside, with a proper kitchen, 2 bathrooms, large balcony (overlooking a busy main road and tram stop) and very spacious living and dining rooms. It's just over 5 minutes walk to the acropolis museum and not much further to the acropolis itself. Easily within walking distance of all the main tourist sites, as well as plenty of cafes, restaurants and bars.
The hosts were fast to respond to messages in advance of our visit and the check in was very easy on arrival, with someone meeting us at the apartment.