tl;dr - stay here.
Trastevere is a hip neighborhood about a half-hour walk from all the main sites in Rome. This apartment is beautiful. It's hip, with lovely furniture, a funky vibe, and everything you could possibly need for your trip. There is a grocery store (Carrefour) a five minute walk away, gelato, and pizza all close.
The host is amazing. She is available for suggestions and help with anything you need. She genuinely cares about the people staying here. I broke my foot unexpectedly while walking (watch out for the sidewalks!) and she called a cab to get me to the hospital.
This is a place you'd like to stay.