I highly recommend staying in Marisol's apartment. The location is fantastic - just a few minutes' walk to the Los Leones metro stop, which is on the most useful metro line. You're out of the fray of downtown Santiago but essentially just 10-15 minutes away from any major point of interest. Plus there's a ton going on in the immediately surrounding neighborhood: it's residential but definitely not isolated. The apartment itself is fantastic, great space with a comfortable bed and bathroom, and the hosts (and Oscar!) could not be nicer.