Lucia is a great host! She responds almost instantly to inquiries (allowing for the time difference between Italy and US), arranged a cab for us and gave us recommendations for local restaurants. The apartment is very charming and super close to metro and the colosseum area; we walked just about everywhere during our stay. Tons of restaurants and shops within blocks. A couple things to note: the apartment is very small--just a sleeping area and a small kitchen with a loveseat and two-seat bar-style table; and the bed is a fold-out, maybe not perfect if you are very fussy about your mattress. There is a small washer but no dryer; we air-dried our clothes on hangars and it worked out fine. There is also a drop-off laundry place nearby.
Also, there is a gas stove but no oven or microwave. We loved staying there and would do so again, but it is cozy! If you are an American coffee addict, consider bringing a french press and some ground coffee.