We had a pleasant stay at Giammaria's. The appartment was as described, clean and comfortable and provided a nice feeling of security.
Unfortunately, Giammaria was not there to welcome us (due to unforeseen circumstances) but his friend who came along was very friendly and helpful. And so was Gammaria in his follow-up communications.
We found the location of the apartment quite convenient with easy access to the tram and various buses. It is a 10 minute walk to the park of Villa Borghese and a 25 minute walk to Termini.
All in all, Giammaria's place is to be recommended for an easy / stress-free, stay in Rome!