Dimitri and Alexandra's studio is really nice, and very tastefully decorated. The location is just amazing! within a few walking minutes to the Aristotelous sqaure, Ladadika area, the tourist information office, cafes & bars, the waterfront, etc.
We stayed there for 2 nights and enjoyed Thessaloniki very much. This city is really charming and has great potential. It kind of reminded me of Barcelona, but with a greek flair. The apartment is on the first floor, but there is an elevator anyway if you need it. The internet connection is very good, especially if you compare it to other places in Greece. It is enough to say, we could watch videos through it.
We ate at the "Last Slice" pizza place around the corner, and had drinks at the bohemian "Nationale cafe" next to it. The atmosphere there in the evening is magical. There is also a small supermarket a few buildings away in the same street where we bought water and essentials.
You should just be careful of 2 things: 1) There is a strange strong smell in the building which is a mixture of soap and something else I couldn't identify. It is not very pleasant, but we were out most of the day anyway. Inside the studio it is not as strong as on the stairs. The second thing is the noise coming from the floor. This was a little distrubing as it woke us up everyday around 9/10 am. Before that it is calm, so if you are a late sleeper, bring earbuds with you. It is not like disco loud, but one hears it well enough from within the studio.

Facilities are all there, we used the washing machine which was a blessing after a whole week in Macedonia. Definitely recommended. Go there.