Our stay at Mario and Annalisa's place was fantastic. Mario was very accommodating, meeting us early on the first day so that we could leave our luggage there so we could go out without luggage our bags around, and come back once the flat had been cleaned.
The apartment is in a great location, we didn't have to use any public transport, the Vatican was 50 minutes walk, colosseum 15, pantheon 30.
I can find no fault with our stay, I would recommend Mario's place to anyone visiting Rome.