We were looking for a convenient location close to the Termini, so we could use the train to arrive from Fumicino airport. The Dem Guesthouse is still new and we thought it offered good value for money and was only a short walk from the station. The rooms are a good size, with wardrobes, a safe, mini bar/fridge, and kettle, plus the bathrooms have cubicle showers and space to put your toiletries. There is also a communal room with a coffee machine and internet access. Devid was very prompt in all his emails, offering us help and advice before we arrived and during our stay. We liked the nearby coffee shop and several of the local restaurants. We will happily recommend this accommodation to our friends. We walked all over the city from the guesthouse and took the Metro from the Termini to reach the Vatican, plus we used the local bus to return from Trastevere.
Just look for the large wooden doorway/entrance opposite the Hotel Morgana on Via Filippo when you first arrive and ring the bell marked Dem Guesthouse. (The accommodation is in a residential style property and there is a small elevator. Request a room at the end of the corridor away from the entrance and reception. The room at the back is larger than the one overlooking the street.)
Enjoy Rome!