Marisa's place is great. It is clean and well stocked with everything you need. It is in a quiet part of Rome - away from the hustle and bustle. It was very convenient for the conference I had at UNINT, and was nice to see 'real' Roman life and get away from Rome's craziness at the end of each day. It may not be for you if you want to always be in the centre of the action, but was perfect for me. It was easy to get a bus to town when I needed to, or to visit the other sites.
Marisa is a great host. She was always quick to communicate with me and was very helpful and friendly. I would highly recommend staying at her place.