I stayed for 3 nights in Donatella's apartment.
the apartment is in a great location, being a very easy walk to bars and restaurants in Trastevere. It is a manageable 20-30min walk to all main tourist attractions in Rome.
The apartment is compact but perfect if you aren't planning on spending much time there. Few downsides - the bed is a small double if there were 2 people staying, the bathroom is a wetroom so it does get very wet and it is quite cold and dark (I stayed in March, I imagine won't be an issue in summer).
That said, it suited my needs perfectly. Donatella was very responsive and kindly dropped more towels promptly when I asked for this. Check in was seamless.