We stayed in the apartment for several days in the end of February. There was enough space for three of us (I think for two couples it also would be fine). Apartment has very good location - close to public transport stations, very close to Vatican, lots of good places to eat and drink, supermarket next door.
It was a bit chilly in the bigger bedroom (because of large windows, I suppose), the small bedroom is warmer. Also in the morning it was noisy starting at 6-7 a.m. (because of the cars coming to the supermarket).
The apartment is very well equipped, having everything you need to cook, and for a pleasant stay.
The bedroom and balcony view of St.Pieter's cathedral is just great!
I would recommend this apartment for stay.