Me and my girlfriend spent 5 days at Joy's place and we had a great time. We didn't interact much with Joy, but she was nice, on time, helpful and her place was particularly immaculate, something other hosts aren't as careful about.
I would definitely recommend Joy's place to anyone who's looking for a nice stay in Rome. The location is also very good (plenty of good pizza and gelato around), unfortunately you still have to walk for about 15min to the nearest underground station, but all in all it was a great experience 4.5/5.