I was a bit surprised by the apartment given the photos and rave reviews. Marco's place is nice- clean, VERY comfortable bed, and though small, about all the space you'd need for a short stay. The building and apartment are definitely a bit dated and the hallway/stairs are downright dirty. I was looking forward to a nice hot shower after a day of endless walking, but the shower head slumped, so I had to lean back in order to get my hair wet. Not exactly relaxing.
The neighborhood and noise: You need to know that Trastavere is considered a nightlife hub of Rome. This was not the quiet, romantic area we hoped for and this street in particular was FULL of bars and late-night revelry. The apartment is on the back side of the building, so it's mostly quiet. However, neighbors were having a party our first night there and kept us up with pumping music til 1:30am (not Marco's fault of course but just what can happen here). The building too is old (part of the charm of Rome, yes) but that means you hear a lot- people walking down stairs, neighbors opening doors... It wasn't terrible but something that was surprising given how many reviews talked about the "quiet" of this place. But Rome is busy and vibrant and it's probably a bit noisy anywhere.
You're also not as close to sight-seeing as is optimal. We walked a TON just to get to the places we were going across the river and took several expensive cabs/Ubers... so factor that into your budget and planning.
Overall- not a bad stay by any means, but there are probably better options if you are looking for more romantic or, certainly, luxurious experience.