We stayed for one night. The views are amazing! The apartment is in a great location close to the Vatican. Raffaella was super responsive and helpful, and even helped with organizing transportation to the airport for us. She also offered us late checkout, which was greatly appreciated.
To explain my overall rating, and in the spirit of transparency (as I expect from other reviewers), here are a few surprises for us: This place has only TWO bedrooms - both with double beds. There is no 3rd bedroom. There is a small love seat/sofa bed in the foyer of the master bedroom, which if opened, no one can get in or out of the bedroom. The unit is on the 6th floor, but the cute elevator goes only as high as 5th - so you need to take the stairs (no big deal but good to know). The AC in the master bedroom had a MAJOR leaking issue, and to make things worse, it's placed right above the bed. We woke up to a sound of stream of water coming out of the AC right over the bed. So we had to move the bed, shut off the AC, and put a bucket behind the bed. I notified Raffaella, and she said she'd fixing it asap, so hopefully won't be an issue for you.
I'd say the apartment is great and comfortable for two couples. Raffaella is also a great host. Issues come up, ACs break from time to time. The fact that she reacted very well to the AC issue demonstrates she really cares for her guests. The only thing that made it a bit awkward for us was that two friends had to sleep in the same bed, which is not what we expected.