We stayed 3 nights at Gemma's, the appartment was very nice, newly restored cozy and clean, it had everything we could need, even the shampoo and the shower gel. The view is what captivated me though, it was perfect. The location was excellent too, just in front of Santa Maria Maggiore, walking distance to colosseo (15min) and to the fountain of Trevi (30min), it is also close to Termini metro station (5min) and there is a bus stop just closeby (but i wouldn't recommend to take to bus, they are almost never on time).
Gemma was very nice, we had a problem in the reservation at the beginning and she was very understanding, the only little problem was that she took time to answer to my messages, and the phone number on her description didn't work at our arrival, so we had a bit of a problem finding the house...
But i would highly recommend this place for anyone who wants to visit Rome, especially for the view, you will not regret it.