Lorenzo's place was fantastic - we think it might be the best airbnb we've ever stayed in. It was exactly as described. The particular highlights were the two terraces, particularly the top one, and the first bedroom, which was really well appointed with a very comfortable bed, nice bathroom, and useful technology (iPad, large tv, wifi etc).. The location is excellent - Trastevere is great fun. Lorenzo was also easy to communicate with and really helpful when we needed a transfer to the train station.

Some things to note (none of which bothered us):

1) The kitchen is small
2) The neighbourhood is noisy at night, but once we had the windows shut we couldn't hear anything. As an aside, the air con works very well.
3) The apartment isn't near a metro station, meaning you have to do a fair bit of walking to get around. This isn't unusual for Rome, but might come as a bit of a surprise to those from, say, London or New York who are used to quite extensive metro services. The city is quite compact and walkable, but just take it slow in the August heat!

Overall this was a fantastic stay and we would highly recommend it.