We had a great time in Buenos Aires and the apartment was perfect for us. All rooms had a window or a balcony so there is plenty of natural light everywhere. All the rooms are comfortable and the kitchen is fully equipped so we were able to cook like we were at our own home when we were too tired to go out. The unit was very spacious which is something we definitely appreciate after our experiences with other apartments in the city, especially in Recoleta area. The decoration and furniture is modest and functional, but this worked in our favor so that we were able to enjoy our stay without worrying about misplacing or breaking something. We had a minor issue with the plumbing and Elena, the housekeeper, was very helpful and sent a handyman to solve the issue right away.
The neighborhood is very residential, but it is important to note that we stayed during the summer, and there is a university less than 150 yards away so during the year I can assume that the area would be full of young people (which still would be great!). Nevertheless, we were still close to the main Buenos Aires attractions and other interesting places either by subway (5 or 6 blocks) or a taxi at the corner of Av Luis M. Campos (taxis are really cheap nowadays due to the FX). I also counted no less than 5 coffee shops less than 3 or 4 blocks away! I would totally recommend the location. The neighborhood of Belgrano is middle to high class so it's very safe and the locals are very friendly. Most of them speak several languages and are welcoming towards tourists.
Bottom line, a highly recommended apartment!