This apartment was the perfect size for my group (a couple, baby, and another adult). I like the high ceilings in the living space which made it feel spacious. The location is right in the heart of things, near Trevi Fountain and Spanish Steps. It's a bit hectic on the streets down below, but peaceful and quiet in the apartment.
We really enjoyed the terrace. This was great with the baby too, because we put her down to sleep one night and hung on the terrace while she slept (note we brought our own monitor to do so, as the terrace is not positioned where you'd be able to hear the baby without it). It was also enclosed in a way that was safe for our 13 month old daughter to play around one early evening while we drank wine.
The hosts were great - arranged transportation to the airport for us and helped with restaurant recommendations. They also recommended a guide, Simona, that we used twice (1 day for Colosseum, one for Vatican) - she was great!