This is my first time writing any review but I felt compelled to do so because I enjoyed my stay in Rome very much for a big part due to this wonderful apartment.
In short:
1. Perfect location
2. Air conditioned
3. Great for traveling with kids, even very young ones
4. Condition of apartment is the best you can do in 400 year old building. Lack of elevator; narrow, worn down stairs take away comfort but add charm and authenticity.
5. Terrace adds to the charm and flexibility for family time.
6. (not the least) Luca is an excellent host!

I visited Rome for 4 days with my family including my wife and 3 kids age 16, 4 and 10 months. We arrived in the evening and thanks to Luca we got a van meeting us at the airport as we needed bigger-than-usual car to accommodate big family and luggage. There was no extra charge for larger vehicle. When we came to plaza next to the apartment Luca was already there greeting us. He helped to bring our stuff upstairs (big help considering the age of the building and stairs).
Inside we found freshly renovated, clean and comfortable apartment the size that you'd expect in 400 year old building :-)
Luca was nice enough to buy for us some staple food for an evening snack and a breakfast so, we settled in rather stress free.
Throughout the stay we enjoyed the central location plus air conditioning. We spent 3-5 hours in the morning to see museums then took a break 1-2 hours in the air conditioned apartment before heading out to see other sights in the afternoon and evening. Location allowed us to walk everywhere: 30 min one way to Vatican and the same in the other direction to Colosseum , everything else interesting is in between.
At night me and my wife were able to put kids to sleep and spend some time on the terrace enjoying the Roman air, wine and each other's company :-) Perfect vacation! Thanks to Luca and this great place. We will be back to the same place because now it feels like home.