We loved Rosa's apartment! It has plenty of room for two people, very light and bright, just as is in the photos. It was very hot in Rome and the air conditioning was much appreciated! The bathroom is a good size, and the washing machine came in very handy. The sound of the bells from the surrounding churches was magical, as was the view from the window. The location was perfect. We were close to everything, with lots of bus options from nearby Torre Argentina, and in reasonable walking distance from a number of museums and sights like Trajan's Column and Piazza Venezio. The little streets around the apartment are filled with fantastic shops, cafés, and bars, plus if you want to go into Campo di Fiore, there is a little alley a few metres from the front door that takes you straight there. Directly across from the apartment is a little mosaic workshop which also runs courses if you were lucky to be in Rome long enough to do one. Their mosaics are beautiful!
We did not meet Rosa during our stay and had no issues so didn't need to contact her while we were there, but she communicated promptly when we needed to ask questions before our arrival.
One small thing we weren't expecting was the additional 48 euro "bedroom tax" we were charged by the Luggage storage place where we collected the key. This might have been their fee for managing the key process. It was fine, but would have been nice to know beforehand. We also needed to supply our own toilet paper, dishwashing liquid and kitchen sponge as there wasn't any supplied. If you need to use the washing machine you will also need to bring your own washing powder. It might be nice for these basics to be available to guests. There is a supermarket around the corner, which was handy.
All in all, this was a lovely place to stay. It's now on the top of our list in Rome and we will definitely stay at Rosa's when we come to Rome again.