The apartment was really nice, modern and spacious with an amazing view from the balcony. It is pretty close to everything so that is also a good point.
Unfortunately, there were a few problems with it though. Since we were staying there during the days when the nights were still pretty chilly, heating was needed. When we got the apartment we were told only the AC could be used for that and when we asked about the thermo and the radiators we were given a really dubious answer that those don't work / should not be used. Since the ACs didn't heat properly we tried using the thermo eventually, that worked completely fine. We didn't understand why it was not told before. A much bigger problem was the issue with the keys. It is an apartment with three rooms and originally we were given only one set of keys. We had to make some rounds with the owner to get a second one, but even with that, it was really inconvenient. We were in Athens for a conference, we had different daily schedules and sometimes we had to wake each other up to open the doors. We even offered that we would pay in case of losing the extra keys. Still, we didn't get more than two. It seems to be a professional business and I highly doubt that there are no more than two sets of keys for an apartment of this size. I feel sorry to write this as this is a nice place to stay, but I hope that in the future this will be changed and it will be easier for others who book the apartment.