My husband and I had a great time in Buenos Aires. It was our first visit to Argentina, we had many questions prior to coming - Marcos was very responsive, he replied to all my inquiries almost immediately and in detail, even though I might have been annoying (:
His place is really great, wonderful and very safe location, a lot of restaurants and coffee places around, metro station is in a walking distance.
At the very end of our visit my husband got sick, our flight home was at night but check out time was 10:00 am, Marcos offered us his other apartment at the same building just to stay and relax before leaving to the airport - it was really nice.