Central to most tourist spots, Samuele's place offers a comfortable stay after a long day of exploring Rome. I loved being able to hang out on the balcony and have breakfast on the little table outside.
Apartment is within walking distance to Roma Termini and the Cavour metro so you can hop on a train easily.
A note to others not to underestimate those four flights of stairs - it definitely provided a good workout, but it will be difficult if you have a lot of lugagge.