Roni's place is absolutely amazing! It's clean, very well equipped, it has a lot of space and very accessible. We (three friends in total) stayed there for 3 nights, and enjoyed every minute of it.
In terms of location, it's located in a really cool neighborhood (Gazi) in which you can find cool bars and clubs. And, the apartment is close to a metro station (two or three station from the city center) or ~20 mins by foot from the city center.
Also, Roni and Styliano (who was the one waiting for us at the place for check-in, on behalf of Roni) were very responsive, flexible and kind to us.