We stayed at Marta's for 4 nights and loved every moment. Gorgeous and well designed space, perfect size for the two of us (potential for 4 adults with the sofa bed but IMHO that would be a squeeze and much less private). We had everything we needed. Nice touches too, water in fridge, plenty of coffee and tea, lovely toiletries. Very comfortable bed and crisp linen, great shower. We hung out for far longer than planned in the morning, just because it was such a cool place to sip coffee and gaze at the fab view from the breakfast bar. The location was better than we expected, a lovely 5 minute walk from the centro storica and down a quiet street a few minutes from the pretty hectic nightlife of Travestere, (I would still recommend earplugs). Recommend local bar 'Chakra' (which you can see out the window at the end of the street) for a nightcap. Really friendly and great wine at a reasonable prices (5 euros large wine or beer). We walked everywhere as it was so easy to get to all the main attractions by foot. Try the ice cream at Fior de Luna, via Della lungaretta 96 and the cocktails/drinks at Fresni e Frizoni, (see Marta's tips) which qualify you entry to the awesome aperitivo buffet. Didn't eat dinner in Trastevere, but if you find yourselves hungry near the Vatican City, don't miss Il Sorpasso at via Properzio 31.
Marta was lovely to deal with, super fast at responding and patient and accommodating when our travel plans went awry with the hire car. The are 4 flights of stairs to reach the flat but after 2 weeks of steep Italian coastal and mountain trips, this was easily doable. Just be prepared if you have lots of luggage and or little ones. Mille grazie Marta, hope to see you soon!