I stayed one month at Domenico's, and I was very happy with my choice! I confirm all the positive feedback others have given before me. Domenico is a wonderful host - very kind, generous and respectful, and ready to help you in any situation. The apartment is beautiful and clean, and the facilities are in good working-order (Wi-Fi, hot water, stove, fridge, washing-machine). The room is very nice: Beautiful sunlight, very quiet, a comfy bed, a spacious wardrobe and a big desk (in case you come for studies). Within only a few minutes walking-distance you find various grocery shops, pizza and ice-cream places, bars, stores, whatever you need. I checked out all the public transportation options: with the 409 bus you can reach the Metro A line (Arco di Travertino) or Metro B line (Tiburtina), and the 105 bus brings you to Termini (but I don't recommend this one since I had to wait a long time for it to come). For me the fastest way to the center of Rome was the yellow train (takes about 15 minutes to Termini, or 10 minutes to Porta Maggiore from where you can take a tram, for example, to the Colosseo).
Conclusion: My stay was a delight, and I hope you will enjoy your stay as much as I did!
Thanks again, Domenico, for your great hospitality!