Daniel and Carla did a wonderful job of welcoming us. They were super accessible on What'sApp prior to our visit and upon our arrival, and I trusted them to respond quickly during our stay (though we didn't wind up needing anything while we were there). They provided lovely details, like a bottle of sparkling wine, light snacks, mineral water, and milk, as well as a SUBE (transport) card pre-loaded with a few trips worth of credit, maps, and recommended places to visit nearby (grocery store, bakery, etc.) Wifi, cable TV...you can even watch your own Netflix account if you're so inclined.
This is a wonderful apartment located in the lovely Recoleta neighborhood, just a few blocks from the Pueyreddón Subte stop. It's on the ground floor, but set back from the street a bit, and feels very safe. Everything you need is nearby - multiple kioscos with snacks and candy, a large supermarket, bakery, and several other kinds of shops, as well as cafés and restaurants. We loved Los Modernos pizzeria (corner of Juncal and President Uriburu) as well as Quotidiano (corner of Juncal and Callao).
The apartment has sleeping spaces for up to 4 people, but it was a good size for 2 of us - 4 might have felt a bit cramped. Side note: there is a narrow spiral staircase to the bedroom on the second floor, so pack light!