I'm not sure if there's enough space to say all the wonderful things that should be said about Valentina and Alessandro and their apartment. The Green House apartment is very close the Colosseum and Roman Forum, between the Monti and Esquilino neighborhoods and short walking distance to almost anything that most people will want to see and do in Rome (the only time we got on a metro train after arriving was to go to the Vatican, and we covered quite a bit of ground). There are two rooms, with a shared kitchen in between. The room we stayed in for our week in Rome was spotlessly clean and very comfortable. The whole apartment is smartly and eclectically decorated, with a style that mirrors the urban, yet still rustic and peaceful setting.
Valentina and Alessandro themselves are tremendous hosts. They respond to messages with incredible rapidity, by far the most communicative hosts we had during our 2 weeks in Italy. They are also incredibly well-prepared for guests, providing maps and dining/sightseeing suggestions. The options for airport drop-off/pick-up and laundry (both for a very reasonable fee) are especially nice touches.
I'm sure that there are more great things to say that I just can't remember right now, but basically, the Green House is an excellent place to stay and not only would I choose it again in an instant, but it's such a great value, with such wonderful hosts, that I can't imagine why anyone would choose to stay anywhere else.