Francesco's place is great! Comfortable, fairly spacious, and very close to public transport. The balcony and enclosed porch are absolute godsends in the hot weather. Opening the door to the balcony and the windows in the porch provides a really good cross-breeze.
Francesco himself is extremely helpful. He provided us with a very useful hand-drawn map showing the nearby shops and transport facilities. When I could not figure out where the boiler was, I sent Francesco a message, and within two minutes he was at the door, and showed me straight away.
Couple of things to note. There is a lot of ongoing work taking place on the Metro C line, which is the one closest to this apartment. As a result, it does not currently go until the final destination. However, there are buses every 10 minutes from its final stop (Lodi), so it's not much of an issue at all. You can get a weekly travel pass for 24 euros, which gives you unlimited travel on the buses, metros trains, and trams within Rome. Plenty of night buses too, so travelling around, in spite of the distance to the city centre, is not a problem. As a point of reference, you can get from the apartment to the Colosseum in about 45 minutes, and that includes any time spent waiting for transport. So the distance is pretty negligible.
Also, Francesco does not speak a lot of English, but he uses a translation service very effectively, and there were never any issues with communication.
Overall, we'd definitely recommend staying at Francesco's place. We'll be returning to Rome soon, and we know where we'll be staying!