I selected Eugenia's place for my business trip based on its location (it was across the street from a project I was working on), but I would happily stay there when on vacation.
The location is fantastic -- the Spagna stop is just down the steps, it's in walking distance to so many sites / sights, and there are almost always taxis a few doors down.
The apartment is spacious and comfortable. It belongs to her family and it feels like you're staying in a friend's apartment while they are out of town (so for travelers who are looking for a blank slate / impersonal experience that a hotel might offer, this might not be the best fit).
Eugenia was super responsive both before my trip and while I was in the apartment.
I would gladly recommend Eugenia's place and I would be happy to return when I'm next in Rome.