I stayed at Alberto & Marialetizia's apartment with my husband, and the room was perfect for a couple. We had the space we needed, and the room was clean and well air-conditioned. The best aspect of Alberto & Marialetizia's place is the location!! The view from the balcony is beautiful, and you can clearly see the Colosseum to your left as soon as you walk out the door of the private building entrance. It's probably less than a quarter-mile from the building. We were able to walk to the Colosseum, the Trevi Fountain, the Spanish Steps, the Roman Forum, the Pantheon, and a ton of restaurants. The metro is also a short 5-10 minute walk. The neighborhood is very safe and very quiet which made sleeping no problem at all.
Alberto arranged for a car to pick us up at the airport, and Alberto was waiting for us outside of the building as soon as we arrived. He was extremely pleasant, polite, and helpful. He responded to any questions that we had via email within an hour or so, and he provided us with helpful maps for our visit when we arrived.
If you're looking for a nice apartment close to Rome's main attractions, this is the place to stay! I highly recommend!