Staying at Victor & Emma's place was just a perfect choice for us. Great location: very centered (just next to The Forum), yet very quiet. Everything and I mean - everything(!) is in the walking distance. We literally walked through the whole city center(from Foro Romano and Colosseo to Villa Borghese and Castel Sant'Angelo), back and forth, every day. We walked even to the Vatican Museums! It took us about 45 minutes but when the weather is nice, it's a really pleasure to take this walk by the river. Also, you can walk to Trastevere neighborhood (about 15-20 minutes). It's a beautiful place with plenty of restaurants, bars and live music... But the public transport is also pretty close: many bus stations just 2 minutes away,the closest train station(Circo Massimo) is about 12 minutes of walking.
Anyway, Emma is a great host, she will help you with anything you need and will answer any question you ask.
We had a great 5 days in this apartment and can only recommend it for everyone!