My fiancée and I just completed our stay at Xystum and we could not have possibly had a better time. If you're thinking about staying here and unsure, do yourself a favor and book immediately. The roof terrace is much larger than it appears in pictures and the apartment is magnificent - I would choose it as my home anywhere in the world.
Alojsia and Mauritzio are the most kind, communicative, and all-around amazing hosts. Our flight was delayed by an hour and neither of our phones were functioning properly upon arrival, so we just showed up hoping that someone would be there to greet us, and lo and behold Maurizio was waiting outside. He greeted us cordially and even helped carry luggage up the stairs, which was extremely thoughtful, although I certainly would not have expected him to do so! He gave us a thorough run-through of the apartment and Alojsia followed-up with written details as she had to go abroad suddenly. Alojsia is extraordinarily communicative and responsive, and you can tell they really put their hearts into Xystum - so many little details such as a fridge stocked with water, a blackboard with notes about the apartment, a guest book with recommendations and tales from other guests, and even a welcome bottle of wine of fantastic quality.
We truly were overwhelmed by Alojsia's graciousness as a host and the neighborhood is as romantic as you'd imagine from looking at pictures. Trastevere itself is a truly fantastic neighborhood and we had the time of our lives. Highly recommended, this was our first AirBnB experience and I could not have possible envisioned how magical it would be, all thanks to the hosts. Grazie mille Alojsia e Mauritzio!