Simone is a great host who was very communicative during the entire process, between booking, arriving and checking in. He helpfully advised us of airport transportation, providing links, and responding right away when my husband's flight was delayed as I was waiting for him at the airport. He was at the apartment when we arrived, gave us the keys, showed us around, and answered a few questions we had before instructing us how to leave the keys when we left.
The apartment itself is quite nice. I liked the look of it right away, with its three sort of levels. I should note that the fridge is quite small, so don't anticipate storing a lot of food in there if you're going to be cooking for yourself. Perhaps leftovers for a day or two, as well as some drinks (Simone was super nice and left us a bottle of wine).
Everything else worked great. We used the stove, microwave, toaster and washer, and that was all very convenient. There's also a table full of local tourist information, and I noticed umbrellas in a stand by the front door. Very thoughtful!
As far as proximity to the major attractions, it wasn't tremendously close, but everything was still very accessible. Right outside of the apartment is a gas station if you're driving, or a tram stop if you're using public transportation. We took the #3 pretty much every day to get to the Colosseum, and from there you can catch the Metro to other locations. To make it even more convenient, there are a couple of Tabacchi / convenience shops on either side of the apartment where you can buy bus tickets. The tickets work for the tram, bus and metro interchangeably, though be advised that if you get a 100 minute ticket, it is only valid for one Metro ride.
All in all we very much enjoyed our stay in Rome, and felt very safe and secure in Simone's place. He was a pleasure to do business with, and I'd be happy to stay there again should we ever again visit Rome. :)