The Wall was a perfect spot to stay and explore Thessaloniki. it is extremely close to Galleria Palace and Galleria Arch (two sites really wanted to experience). Not too distant and easily walkable are the White Tower and waterfront, as well as Odeon, Ano Poli (old town) and the north city wall, though the latter is an uphill climb. Good restaurants (Lola's is a highly regarded seafood restaurant, just steps away), markets and shopping are close by..
The apartment is spacious and quiet. We loved the two balconies, but gravitated to one off the living area, for eating and drinks. All appliances worked efficiently, which was welcome for a little cooking in (we didn't do too much because of the plethora of choices to eat out.
The stairwell is dark and never figured out how to use the lights there, but we normally opted for the elevator anyway. That was very welcome, with a fifth floor apartment.
Giorgas' apartment is great place to stay and I would recommend it without hesitation.