First and foremost the hotel is very nice - it is modern, clean, comfortable, and well located.
The rooms are basic but well appointed, and if you’re lucky you’ll get a sea view (as I did). All rooms have balconies with seating. Oh and the breakfast is excellent - lots of choice and the restaurant area is clean and spacious.
I get the impression many travellers use this hotel for short stays either for late arrivals into Athens for travel elsewhere, or the end of a holiday before flying home. To that end, the free shuttle to and from the airport is an excellent add-on. Easy to find at the airport and only a 20 mins drive away.
There is not a huge amount to do in Rafina, though it is a cute little port town with plenty of cafes, restaurants and local shops. St Nicolas chapel is worth the short walk.
Overall I would recommend Avra for visits to Rafina - does the job and is well priced for what you get.