Excellent location. It would be difficult to get better. Walking distance from the Colosseum, the Forum, plenty of shops and Trattorias. There are two good supermarkets on Via Cavour (the far side from the apartment) so you can stock up on basics!
If I had to find a flaw, it would be that we could not get the air con working. Be sure Massimo shows you before he leaves!!! And there was one wine glass in the cupboard...very small, first world problem!! Highly recommend for the location, cleanliness and value.