I can't imagine better location for Rome trip (other than with direct view of some monument like Coloseum).
Fontana di Trevi is just few steps away. Directly in front of you are caffes with great food. Most of the monuments are just short walk away. Great restaurants and bars as well. It's just an amazing location.
The apartment itself is exceptionally cold and is nearly impossible to heat it up due to hight ceilings and big rooms. This is a big problem in colder months. But I can imagine it's great in the summer. Also the shower is extremely small. It's possible you won't be able to fit in, if you are even more obese than me. Water pressure and temperature is another issue.
The last thing. Host will offer taxi ride for 60 euros. SIXTY. You could take bus+train for 2.70 per person to the main train station and then uber or alternative for around 8 euros. On our way home we took local alternative to uber FREE NOW, and the whole trip was 32 euros. When we asked for help with direct shutle bus, they told us only not very specific information. I didn't like that at all.
Location 100/10, Apartment 7/10, communication 5/10.