The location is fairly central and not hard to find. Likewise, the accommodation is cheap and the owner is a good host, displaying friendliness and excellent communication timing.
However, the apartment is very cold, so I don't recommend staying there in the colder months and their heating units don't work very well (they are merely AC/heating units which turn off if you leave the apartment). The bathroom is also very small and the water heating situation is a little awkward.
If you go in the summer months, you can be sure to have a great time there. If, however, you wish to visit Thessaloniki in the colder months, then I think it might be advisable to go elsewhere.