We had a really lovely stay at Lorenzo's apartment. The location is really great - we walked everywhere (except to the vatican). It is very close to the Roman Forum and the Colosseum. And we found a lovely area with lots of restaurants (a gluten free one too) on Via del Boschetto and Via dei Serpenti.
The apartment is very small (just one room with a sleeper couch, table and kitchenette) but it has everything you need and is very clean and modern with everything in working condition. The only things that were missing were a few kitchen appliances - there were no bowls or butter knives, and no kettle. However the kitchen is very small so maybe many people eat out everyday.
Lorenzo was a lovely host - he met us early (as our flight came in very early) and showed us how to unfold the bed etc and gave us advice on getting around and to the vatican especially. He was always quick to respond as well if we had any queries. I would definitely recommend staying here - especially if you do not plan on cooking very much during your stay. The location is the best feature and that is worth everything.