My group of 4 very much enjoyed our stay at Tamara's. The apartment is centrally located and close to shops, restaurants, a grocery store, public transportation and sites; we sort of "bumped" into Trevi Fountain without even realizing we were headed in that direction. The space is very clean and comfortably accommodated our group.
The closest metro station, Barberini, is closed and has been since last spring if I'm not mistaken. However, we never had a problem catching a bus just a block away; and Spagna metro station is a 10/15 minute walk away. Our 7-day metro pass was worn out by our last day.
Tamara/her team always responded to our questions and requests in a timely manner. She even arranged for a car service to and from the airport; it was actually slightly cheaper than if we had taken the express train from the airport to Termini station, so definitely crunch some numbers to see what works best.
Lastly, Tamara met us at the apartment for check-in, gave us details about the place, area, and left us a bottle of wine, treats/snacks, soap, etc. All very generous and charming. Would definitely book again!
Note -- Tamara mentions this in her listing, but worth highlighting: In addition to the booking price, you will be charged a €3,50 tourist tax, per person, per day. Tamara provided a receipt and we left the amount in cash at the end of our stay. She will also require your passport information to register guests with authorities, either by taking a photo of it or in writing; we opted for the latter.