This apartment is a fantastic place to stay while exploring Rome.
Location-wise you couldn't ask for a better base to walk to all of the major sights. There are some great restaurants close-by too (definitely worth going to Voglia da Pizza, but also the small pizza place below the apartment - they do takeaway so you can grab food and take it up to the apartment). The restaurants and bar beneath the apartment caused us no disturbance, with the windows closed you could barely hear them - and they were great for a drink in an evening too.
We stayed with our 5 month-old baby, and overall the apartment worked great for us. Lots of reviewers have mentioned the steep stairs - we didn't find these to be a problem, even with our larger pushchair (we folded it to carry up and down).