My wife and I stayed at Ventisei Scalini a Trastevere for our anniversary and couldn't have been happier. Our room was spacious, immaculately clean and very comfortable.
Despite never meeting in person, Lucia was a wonderful host and we couldn't have asked for more. We were late arriving but gaining entry was simple and straightforward. We had far more than we needed for breakfast including fruit juices, tea and two different types of coffee. Being on the ground floor we also benefited from a small outside space, perfect for the two of us.
The location was ideal. We were a short walk from the Tiber, which was great to stroll alongside of an evening, and if anyone was looking for a little more nightlife, the main restaurants in Trastevere were a short walk in the other direction. On our first day we bought tickets to use on the metro but didn't get on it once. If you're happy to wander you can easily reach all of the main "tourist" sites. We walked to the Colosseum, the Pantheon, the Spanish Steps, the Trevi Fountain, Castel Sant'Angelo and St Peter's Square and Basilica and so much more.
We cannot recommend this place enough. Do yourself a favour and book a long weekend. You won't regret it.