We stayed in Cornelia House for a week. I think we couldn't find a better place to stay in Rome!
The location: just great! Very safe. Extremely close to the city centre thanks to the metro station just around the corner but still far away from other tourists and annoying vendors, which was just perfect. :)Good shops and very reasonable prices, and also a great coffee bar with amazing Italian coffee next to the flat.
The flat: everything was as described. Very cosy and tidy, a comfortable kitchen with all appliances. Bathroom - clean and fresh. You get towels, toiletries, an iron, etc. We were very happy there.
The host: Marco and his family definitely helped us feel like home. :) Very trustworthy, helpful, and so very nice!

We'd definitely came back there if we had a chance!