We stayed 4 nights around new year's eve at Carpe Diem.
It is true that we are well received. Roberto had prepared some welcome gifts (wine, chocolates, baby panetone, marmelade). Appart is comfortable (very firm mattress if you want to know), well heated in winter, clean and you hear no noise from the street.
The detail that was not as good as we hoped was location. We had to do multi-buses travels. But that's no big deal. And we prefer that to Termini, where buses and metros are often overcrowded.