My parent's had a great stay at Mariam's. It's large, clean and stylish, and as described and shown in the pictures.
It's well located, close to the sea front and a nice park, near the museums and a short walk from the centre of Thessaloniki. There's lots of buses that pass by and a taxi rank close by if you need to get anywhere quickly. There's a good bakery a couple of buildings down, and a coffee shop that does good coffee.
We didn't actually meet Mariam but communication over the app was perfect.
I'm sure I'll book Mariam's place again.