Yiannis is a wonderful host, he welcomed us with wine and sweets, explained where everything was and what was definitely worth visiting. He was also very responsive, which I truly appreciate.
The only not perfect thing was the height of the bathroom (it's a bit low), but it's definitely not a deal breaker, and all in all, it's a small thing.
I will consider Yiannis as my first option the next time I go to Thessaloniki :)