The location of this apartment cannot be bettered: it is within walking distance of basically everything. The apartment itself is large, light and airy: the wraparound balcony with the big windows is a huge plus. The apartment is spotlessly clean, the beds are comfortable. Sofoklis is easily contactable and will help you with anything you need.
One minor point when we were there is that the kitchen equipment was not quite up to scratch: not really enough cutlery and no cutting knives. I'm assuming this is merely an oversight and will be rectified soon.
The reason I didn't give it 5 stars is that this apartment building has zero sound insulation, so prepare to be woken up by the yappy dog of one of the neighbours and being able to time the kids upstairs practicing their 10m sprints at regular intervals. If you can live with that, then I don't think you can get better than this.