We spent four nights in Trastevere and it was absolutely fantastic! Massimo and Paolo were very friendly and helpful, and took the time to recommend us the best places to go to. The apartement itself was perfectly located in an area that's not too touristy but still in walking distance of all the main monuments and places to see. We only took the bus from and to termini station which was direct and convenient.
There is a little morning market on the square outside the apartement and a lot of restaurants and bars within five mins walk. We didn't find the area to be particularly noisy, and it felt safe.To go to the vatican there is a wonderful walk that only took us thirty minutes through a beautiful park. Overall I definitely would recommend this place to anyone.
the only downside would be that the deco was a little dated and we couldnt find any wine glasses ;) (really only minor issues!)