Ralf's flat was a perfect place to stay. Very good communication with metro (subte) and buses (colectivo). The cheapest way to get from the Ezeiza airport is taking Manuel Tienda leon bus to the center and changing to the metro. It takes around 1.15 hours to get to the place.
The flat itself is as seen on the pictures, even better. I liked the design of the flat. The building has a swimming pool, spa and a small gym free of charge.
Next time I go to BA I will definitely stay at Ralf' place.
Check in and check out was perfect. On my last day I was let stay till late.