Gabriele place is the place to stay if you want quick access to the main attractions in Rome. Bus 98 brings you to Paola station close to both the Vatican and the city center in about 15-20 minutes. There is also bus N15 if you want to enjoy the city during the night. The access to Termini station is also easy using buses H and N15.
The person that is in charge with the apartment is a nice and sociable guy that will give you all the information you need. Bonus: his coffee is great!