I can only say great things about Nicolo; he is a friendly host who care about making your experience as pleasant and streamlined as you would be expect. Nicolo is very easy to reach in person or by message and he will quickly address any specific concerns or general questions you may have.
As for the house itself, it is large and we'll furnished. I enjoyed the 2 bathrooms which is good when everyone is rushing in the morning to take showers. The bed is also clean and comfortable.
The closeness of the metro subway station was a huge plus and really made things convenient for us. There are a lot of good places to eat nearby which is great when you arrive at night after a full day of sight seeing and hungry but doesn't want to go too far to eat.
The full kitchen is great if you plan on doing any cooking. I would highly recommend staying at Nicolo's place if you ever visit Rome.