Our group of 8 found Trastevere Deco perfect for our needs. There are 13 beds (11 actual beds plus a 2-person sleeper sofa) spread among 6 bedrooms, with 3 full bathrooms. The living room/dining room was large enough for us to gather to discuss plans for the next day, when we weren't gathering in the large kitchen.
The apartment is located on the third floor of a 4-story building, with an elevator, which was important to us because we had 3 people in our group who have trouble with stairs. (The elevator is small - it fits 2 adults, or 3 people if there is a child.) If you enter the apartment through the front door from the main road, there are about 12 steps leading up to the main floor of the apartment building, where you can either catch the elevator or simply walk up 2 flights of stairs to get to the apartment. However, knowing that we had some people in our group with stair issues, Flaminia and Alexandra gave us a key to the basement which is accessible from the street level (around the side of the building), which allows you to not have to climb any stairs in order to access the property because the elevator goes all the way to the basement.
The wifi was very good, and we appreciated that the apartment had deadbolts to lock from the inside when we were in for the night. The building was very quiet (we saw only 4 or 5 people in the building the entire week we were there). Flaminia and Alexandra were amazingly quick with communication, and they were so helpful - they even ordered us vans to pick us up from the airport and take us back there. The apartment was very, very clean, and stocked with plenty of towels and linens. In the kitchen were a microwave, fridge, freezer, gas stove, dishwasher, washing machine (no dryer), kettle, toaster, and plenty of plates and cups.
The apartment is located in a nice part of Trastevere; we never felt unsafe while we were there. We decided we wanted to stay in Trastevere because we had heard it was a cool neighborhood, and we knew we'd be spending most of our days sightseeing across the Tiber in the historic center. So even though we took cabs every day to leave and return to the apartment (we never attempted to figure out the public transportation system), we didn't mind because we wanted to be forced to explore as much of Rome as possible. There are several restaurants within 200 feet of the apartment, and even more (and gelato shops) within a half-mile. We would happily stay here again!