I stayed four nights at Theodoros' place over Christmas. Apartment is fine. Very cold and the heater put in the room didn't make a difference at all. Not central to Athens. At least a thirty minute walk to the train or a five min walk to the bus and then another train.
My issue was that I paid for two stays with three days break in the middle to visit my sick grandparents. I left one night early so paid for that night anyway. I left my big bag there with the room tidy which he was ok with. Then I messaged while away and said that I had changed my flight to leave later as my grandparents need help. I wanted to cancel the second booking for three nights and stay the last night only because he would make enough from the cancellation fees and the extra night I paid for to cover the inconvenience of storing my bag and the last night. He told me I couldn't stay the last night because all of a sudden "he was hosting friends" for the dates I had already booked. When I got there, there were no other guests. Just seemed a bit petty. So I had to collect my bag and find a hostel after 10pm at night. Overall left a really bad taste in my mouth as I thought it was very unreasonable considering all the extra money he made off me. That's what it's all about in the end though right? Making money. I would stay a lot closer to monastiraki next time I visit Greece.