I stayed here a few weeks ago, prior to going to Kea Island.
It's too close to the city to be a resort, yet too far away to be a city hotel. It sits in some
Schrödinger's Cat alternative universe of properties. You can hear the traffic and feel the city, you can see it with your own eyes, but you're not.
Just like Kea Island, privacy is a severe factor here. The gardener needs to start juicing his fertiliser or something as until the plants/trees, etc, have grown, it's like a free-for-all to spy on everyone. Even when they do fix that, some of the outdoor areas benefit from little to no privacy. We stayed in one of their top one-bedroom suites - Riviera Bungalow Suite Seafront - and to get to the beach involved walking past someone's room, whilst our courtyard had two rooms overlooking it. We could look-up and see people in their pools from our pool. Your room is someone else's Amphitheatre.
Parts of the hotel feel extremely generic, like the beach area, which is swamped with chair after chair. Others, are really beautiful. As it's a One&Only, the Kids Club is superb, and the gym and spa are decent. The food was fantastic, too.
Service was very mixed. I didn't feel there was any laziness, just a lack of remembering and constant not understanding what we were asking. Housekeeping coming five hours after we asked was annoying. Like most One&Only's, you have a host that you communicate with, who isn't a butler, more like someone working at reception that's dedicated to you. Your experience is going to really vary depending on how good they are and ours was very forgetful and inexperienced.
My initial impression was: a wonderful hard product and a terrible location, making me think, “What’s the point?”. I really did struggle to understand the purpose of this place, as no one surely comes to Athens to not be in Athens. You're not paying for some superb beach/view here, in fact, you're mostly surrounded by derelict buildings.
Still, I would pick it over Four Seasons, which I struggle to see the point of even more.
Pictures: https://dorsiatravel.com/oneonly-aes...d-photo-album/
Side note: I stayed in Grande Bretagne about five years ago, and you would be right not to bother with it.
This might be worth a look https://www.thedolli.com