We stayed at Mario's apartment for 2 weeks late Nov / early Dec. Mario is a great host, he is very polite and will go out of his way to make you feel confortable. He takes great pride in his home, and it shows, there is a lot of great art and decor in his apartment, it feels like being in a museum. Everything is clean and spotless. The apartment can get a bit cold during the winter, but the bedsheets & comforter kept us warm & toasty throughout the nights, plus there is a heater. We only saw Mario 3x during our entire stay, and sometimes it felt like we were the only ones in the whole apartment (he's a hard worker!). The bathroom is very clean and big, and the kitchen is fully stocked. He provided us with bread, eggs, milk, jam, pastries, and biscuits, and even gave us a bottle of wine and mozarella as our welcome snack! Wi-fi is also good.
The apartment itself is in a great location, it's outside of the tourist bubble of Central Rome, but literally a 5 minute walk away from the Metro station. (It takes about 20-30 mins to get to the city center, depending on frequency of trains.) There is a supermarket down the block, as well as 3 grocers if you want to cook for yourself, and 4 pizza shops within a 2 minute radius. A nice park is nearby too!
The one downside (and it's not Mario's fault at all) is that the neighbors on the other side of the bedroom wall are very loud. The wall seemed quite thin, and you could hear the neighbors talking ("yelling") quite often. They also would leave the TV on all night with the volume up. The neighbor is also a very loud snorer, it felt as if he were sleeping right next to us! Bring earplugs just in case!
Overall, I would highly recommend Mario's place, it was a comfortable home for two weeks, and we would definitely return again!