Kostis is an amazing host!! We came to Thessaloniki without knowing what to expect or what to do but he sat us down and gave good recommendations for food and interesting spots as well as a bit of local history. He was also responsive to messages and you can tell he cares about you having a good experience.
The apartment itself is beautifully designed, functional, and easily fit the four of us with plenty of room to relax and eat. You can tell a lot of care was taken into making sure guests had everything they needed.
To keep it short, if you are in Thessaloniki, Kostis's is the place to go!