My wife and I loved Marina's apartment in Trastevere. We came by train from Milan and Marina welcomed us at the apartment with all of the information we needed and even lots of treats. The apartment itself is roomy, comfortable and lovely. We were so grateful to have a clothes washing machine as well. Also, the location is great. If you do not know Rome you will find this is a perfect spot from which to explore -- all of the major sites just a short walk across the river, and the lively Trastevere neighborhood is all around you. You're also close to major arteries for the bus and tram system. That said, the apartment is quiet at night -- close enough to night life, but not so close you hear people partying at night.
Be sure to ask Marina for restaurant recommendations also. She is a wonderful host.