We stayed at Marco's for almost a week and had a great time. It is a bit far from the historic center, but easily reachable by bus or metro. We mostly walked - it is about 25-30 minutes to Colosseum and 20 minutes to Orange garden. The room is good, comfortable bed, air conditioning turned on automatically at first night, but then we managed to turn it off as it was not so hot :). We also had wonderful Italian breakfast at Andreotti's pasticceria downstairs.