Madeline and Barbara's place is perfectly located if you want to explore the Trastevere, Piazza Navona and Pantheon areas. Lots of great food and cute shops nearby, but the apartment itself is not on a super busy street. (Though being on the ground floor you'll still hear people walk by late at night if you are there on a weekend.)
Madeline and Barbara are interior designers and it shows; the apartment is beautifully decorated - the pictures do not do it justice! - and is very spacious and comfortable. Their shop is right around the corner, which made checking in super easy.
They were also super communicative and helpful with recommendations, and even helped us schedule an early morning taxi for our departure.
We loved our stay with them and would definitely go back!