I was with Valentina and Vladi for 3 weeks while working voluntarily in the city. I feel like they were more like flatmates than hosts and we did so many fun things together; they took me to La Vega during the weekend, we cycled up San Cristo after work (they had an extra bike) we played card against humanity until early morning with their friends, and I can't even start to count all the internal jokes we have after this time. They were really caring, flexible, protective (either always walked behind me at La Vega to make sure nothing would happen to me or my camera) generous (shared food and lots of tea!), and helped me so much (both with suggestions on what to do, getting a cab to the airport, asking if I needed anything when I got sick, but most amazingly Valentina went with me during work hours to a bus company after they had messed stuff up, and helped me ask for my money back and called them later, and wrote the e-mails for me). I could not have imagined my time there to be any better and I'm going to miss them!
With regards to the place, it's on the 9th floor with a great view, a gate and a security guy, very close to a supermarket, and good bus connections to the metro Salvador. The entire area is very safe too and quiet. I would not just recommend them, but also do it all over again - and for longer if I could!