I stayed here for 2 months, so my review may be a little different than the others.
First of all, the location was PERFECT for me. Close to the Metro (5 mins), train station (7 mins), and bus system. The neighborhood is quiet and safe with plenty of restaurants around, but only 10-15 minutes from the touristy sights around Rome. Trastevere was an easy 20-minute walk, Colloseo was a 10-15-minute walk, and you could be in the Capitoline area in 10-15 minutes as well. For those of you interested, the UN FAO building is exactly 8 minutes door-to-door. The surrounding neighborhoods (San Sabo, Aventine) were also fun to explore. There is a general store, grocery store, and several ATM's close by.
The apartment is very spacious as described. It is on the 3rd floor but there is an elevator provided. Neighbors are quiet (there was no one living next door during my stay). The bedrooms and bathroom were large, especially for European standards. The small balcony was nice as well - several previous reviewers noted the street noise, which can be quite loud, but I am a heavy sleeper and it hardly bothered me (except when they collected the glass recycling bins outside at 5 am....) Lots of closet space, and beds were firm but comfy.
The WiFi worked great except for a short span of time when the entire neighborhood was out of service. There are 2 TV's that get all of the basic channels (most in italian but 2-3 channels could be set to english).
The shower is a little small and the water pressure was really, really poor. This was noted by previous reviewers. I cleaned it out several times and contacted owner to replace, but this was not yet resolved when I departed. Given the very hard water, I am not surprised that there are constant problems.
The only other problem I had was that you could not run any two large appliances at the same time such as the air conditioner, stove, dishwasher, or laundry washer. This was a little inconvenient during the heat of the summer months, especially since the clothes washer ran on a 45-60 minute cycle. This was noted by previous reviewers, and fortunately Riccardo showed me the location of the fuse breaker and I only managed to trip it around 5 times during my stay.
Riccardo was very accommodating for check-in and check-out, and responded to texts quickly. Overall I would recommend this apartment, and definitely will try to stay here again next time I go to Rome.