We had a great stay at Luis's apartment! It's very comfy and cosy and the bad was just amazingly comfortable. We slept like babies! :) The apartament has a great location - quiet, but still at the heart of Trastevere. Luis is a lovely, caring host. He gave us a lot of advice about good restaurants, cafes, about transportation and sightseeing.
Some people wrote about problems with hot water. We didn't have any, there was plenty of hot water for both of us. The heating also worked perfectly. There's very good hi speed Wifi and a tv with a huge choice of channels.
I strongly recommend choosing Luis's place! Renting a flat in Rome couldn't be better :)