Location, location, location. I’m convinced there’s no better place to stay in Thessaloniki. The White Tower is literally 100 m away and anything you want is within walking distance. Tons of restaurants and cafes nearby, as well as smaller convenience stores to stock the kitchen. Check-in was easy and Hlias is a prompt communicator.
The unit itself is very spacious! Large living room, large dining area, and a large bedroom with comfortable bed. The shower is very nice and the water was sufficiently hot.
As noted by others, the unit is on the fifth floor and requires about 90 steps (5 floors times 18 steps per flight). Note that steps are smaller in Europe than the Americas. Not a big deal but something to be aware of if mobility is a concern. Plus, it helps justify all of the delicious Greek food you’ll be eating.
10/10, highly recommend.