Staying at Cristina's place was great. It's really good located, you can reach the Colosseo by foot and the subway is just a 5min walk. The room was nice and clean, as was the bathroom. My friend and me shared the appartment with two other Airbnb-travellers and Cristina's dog Brando (who likes to cuddle). I can't say too much about the kitchen or grocery stores nearby though, since we ate out during our stay.
I can definitely recommend Cristina's place, she's a nice and attentive person. Thanks!