We traveled with 3 Kids and stayed 5 nights with Rosa.
Pro: appartment has a lot of space and accommodates 6 persons easily. Walking distance to subway is ok (15 min), neighbourhood feels save and is calm at night. Rosa is impressively quick in responding and always very friendly. There are plenty of towels, pillows and blankets. The bakery Gian Piero around the corner is awsome.
Con: the appartment needs a renovation. It is worn out. Unfortunatly it was not very clean. You do not want to walk without shoes or drop anything onto the floor. The kitchen is not equipped for cooking or even preparing breakfast. The neighbours upstairs like to listen to rock music.
Bottomline is: if you only sleep there and your expectations are not high, it is ok because of the price. But if you want an accomodation to spend time or get a rest from sightseeing, you should probably choose something else.