Small, well equipped and very clean flat. The metro is just a stone's throw away, you can be in the center of Athens and the tourist attractions in ten minutes.
I warmly recommend the fruit and vegetable shop, Ioanna's, which is opposite the railway.
I also recommend to cross the railway to visit the district of Sepolia with its restaurants and cafes.
I stayed almost a month in Marios' studio because I was on an internship. I enjoyed it, but I think it's more interesting for short stays in terms of value for money.