I'm thankful to the host for a warming welcome and for the future guests I'd like to outline some pros and cons.
Expected pros: well-furnished apartment with everything you need for a long stay (kitchen facilities, washing machine, microwave, bidet, etc.)
Unexpected pros: an access to a terrace with a view of the district - very cozy. Expected cons: location - even though it is an only 1-minute walk from Cornelia metro station, it is very exhausting to get home after a long day of sightseeing (10 metro stops from the Termini). So the apartment is suitable for a stay of at least 7 days, for a shorter stay, I'd definitely recommend to find an apartment located in the city center.
Unexpected cons: quite noisy and badly smelling district; uncomfortable bed and shower; fourth floor without elevator.
Despite the cons, the overall experience was rather positive.