Roscioli is uncomfortable and a bit of a tourist trap. They serve largely the same menu plus more a couple of blocks away at Emma, which is much nicer. Try the black truffle mortadella served on hot pizza bianca. Reservations essential.
If nobody told you to go to Da Remo in Testaccio you’re not getting the right local advice on pizza. Their prosciutto e melone (if in season) and visciola (sour cherry) tart are also great.
Trattoria Perilli is my favorite for carbonara and coda alla vaccinara. Reservations essential.