Awesome location, very central to be near many restaurants and a short walk to the Parthenon. A little further of a walk away is the Trevi fountain and Spanish steps. Buses are easy to get to the Colosseum, Vatican or galleries (you could potentially walk there too but with Rome summer temperatures in 33C-39C (90F-100F) it's best to avoid being in the sun too long.
In terms of drawbacks (mostly mentioned in other reviews already): The apartment is up several flights of stairs (no elevator) so can be tricky initially with large luggage. On the plus side, it's very quiet. There wasn't much hot water in the shower (we only had some on the first day, but we managed). There can be a bad smell in the bathroom sometimes but that is probably common with older apartment buildings.
The apartment is well stocked with towels, toilet paper, soap etc. The design is compact and very functional. The clothes washer was very convenient as we had taken a long trip.
The kitchen is also very functional, with a stove and dishwasher. The bed was comfortable and there was also a fold out couch. The air conditioning was also a real bonus given how hot Rome was.
I think it mentioned "breakfast included" but don't expect too much. For us this was Nespresso coffee. The host was also kind enough to leave us some wine and chips.