We visited Rome for 4 days and stayed at Marco's place. It was a nice experience. We were 4 people and the house was perfect for us. There was a sofa-bed which was good enough. Marco gave us warm welcome and explained everything.
The best part is that the location is perfect. The bus stop and metro station (S. Giovanni, Line A) both were very near to the house. This is essential to visit Rome. Colloseum and Forum were just 15 minutes by bus. Marco also dropped us to the airport by his car with a chip price.
I strongly recommend to stay in his house. If we go again, we will stay again.