Mirko and the apartment is fantastic! We drove to apartment in the evening coming from Pisa and Manarola and got caught up in the traffic. Mirko ended up waiting almost 45min for us, and kept a parking spot ready for us! He is really friendly, and got all the information you need.
We were a bit skeptical about the view and pictures, as some make it sound and look better than what it is. But to our surprise, it was better than what is shown, and neither words nor pictures do it justice. We could easily see Coloseum and a good view of the rest of Rome, and ended up having dinner and a bottle of Piemonte Brachetto on the terrace.
It close to mostly all the big things in Rome, being within 30min of The Trevi Fountain and Spanish Steps, and just a bit longer to reach St. Peter's.
P.S If you're crazy about Crepe de Nutella (pancakes with Nutella) then do yourself a favor and get one from Venchi, not far from The Trevi Fountain. It's a big piece of heaven! (P.P.S they also have amazing ice cream - yeah, we went there twice!)