Perche, are you familiar with LA Residenza on Via Emilia? We have stayed there a few times and thought it was quite nice. We haven't been to Rome in several years but did enjoy our last stay. We were fortunate in that our room came with a very large private terrace where we would drink wine and eat local delicacies..Quiet street yet easy walk to borghese gardens, Spanish Steps. Actually walked just about everywhere including Vatican. Breakfast is really fine
We have recommended this to friends and family all of whom enjoyed their stay