We really enjoyed our stay at Nicolas's place. The building caters to travellers and short term rentals so it's well set up to accommodate that type of clientele. There is a 24 hour doorman and a few different places you need to use at card to gain access to the building so it seems very safe and secure.
The apartment is very well located basically in the very center of the city. Close to two different subway lines and many different buses. You can pretty much walk to all the major attractions in the city.
Also, it's right beside a Lider which is owned by Wal Mart so if you want to get stuff to snack on or to cook food you can get all you need steps away from the apartment.