Elena's place was lovely. Very close to the Colosseum and a couple of Metro stations and bus stops. Not to mention a lot of very good restaurants in easy walking distance! We ate at a different place almost every night.
The apartment itself is cozy, up two flights of stairs or a quick jaunt in a little elevator. There was construction noise a couple of days but I don't think it's common for this area. You are right across a hall from a neighbor so you may sometimes hear them going in and out. There's a heater/AC unit, as well as plenty of blankets, so we were perfectly warm our whole stay.
I have to say, having a cup of tea on the balcony with a view of the Colosseum was a great way to spend an evening.