We were warmly greeted by Dario, who waited past the agreed time (we were "street confused") in order to greet us. He gave us many valuable tips for having the best visit in Rome. He was also available by email and phone whenever we needed him.
The apartment was clean, roomy and bright with two very large windows for light and a nice breeze. Although there was A/C, we had no need to use it.
The apartment was also very conveniently located and close to the Metro although we never needed to use that either. If you enjoy walking, the Coliseum is about 25 minutes, the Vatican about 55 minutes and the rest of what you might want to see readily walkable. A market, a number of bakeries and lots of Gelaterias are also close.
Overall, we would definitely recommend Dario's apartment for a thoroughly enjoyable place from which to explore Rome