I stayed with Massimo for a total of five nights and had an excellent time. Massimo was a fantastic host; friendly and very helpful, with perfect English. The flat is about 10 minutes on the metro from Termini and really easy to get to, so navigating the city isn't a problem. Being outside of the main tourist area, it's quieter and more local, but the great thing is there's still lots of very good restaurants nearby, of which Massimo has great suggestions.
All in all, I had a great stay and it felt just like home. Very laid back, clean and tidy, with an attentive host who is easy to keep in touch with.