I flew Prima Business (not Magnifica Class which is long distance) and I was in transit in Rome on 2 international flights.

The lounge I was in was by the gate near the stores and coffee shops. There were 2 lounges. The smaller 1 was for Alitalia only and the other much larger 1 was for about 30 different airlines.

Both lounges have no windows which is a bit claustrophobic. In the morning they have sweet croissants and in the evening some nice small sandwiches. What I liked was the different fruit juices; apricot, pear.

I don't remember seeing showers. In mid morning lounges are full but around 7pm empty which is much more pleasant.

Check on the Alitalia web site.They describe the lounges I believe.