Panagiota's place has a great location with a terrace overlooking the Church of St. Demetrius, and a beautiful old mosque (now restaurant/nightclub). It's quite easy to get to, and is a good location to visit lots of the sites in Thessaloniki. There was a little bit of noise (the neighbor upstairs is remodeling-this certainly isn't Panagiota's fault and he will finish eventually!) and some noise from the club near the apartment (but only on the weekend), but it isn't too bad and I usually bring earplugs with me anyways.
I never met Panagiota, but she was quick to answer any questions and checked up on me regularly.
The apartment is nice, comfortable for two people, bathroom clean and quite good shower. It is a simple, cozy apartment with some nice touches. I would stay here again.