You can't get a better location to go and stay in. Christos is an understanding and attentive host and answers any issues very quickly. We were grateful that we were allowed to leave our bags at the flat earlier than the check-in time.
The flat is spacious and bright. Heating and air conditioning work well. Sound proofing of the flat is also good. You do have people living above and below, so you'll get a bit of noise at times which is totally understandable. Don't forget that you are right next to Tsimiski street, and at times the traffic roar can be ecophantic and therefore even the sound proofing can't stop absolutely everything.
Furnishings are comfortable and good quality. The kitchenette is handy and you can do some food prep there if you need to. The front door is reassuringly secure, it clunks shut when you lock it as if it is the entrance to a walk-in safe.
All in all, it's a very comfortable place. We would definitely come back!