This place is great. The Lastarria neighborhood is awesome. It's only a few blocks long but is where all the action happens. It's very lively so on the weekends there will be some noise - but that is what we wanted. A fun location where there were plenty of bars and restaurants. It was very safe to walk around this area, and a quick walk to the metro or to any of the sights.
About 10 minute walk to Bellavista, 2 minute walk to St. Lucia Hill. 15 Minute walk to Plaza de Armas.
The restaurants around the apartment are amazing as well. All a bit pricey for the city, but it's a nice young hip area. Think of Williamsburg, Brooklyn, or Decatur, Atlanta.
Kris and Fran were great hosts, while we didn't connect face to face, they made access very easy, the doormen and women were lovely and fun, and the hosts stayed in contact with us throughout the trip.
If I come back I would stay in this same exact location and would recommend it to anyone looking!