A CNN correspondent has tried out Mr. Go, the 3-minute pizza-vending machine in Rome. The verdict is that it's a cross between pizza and piadina, not a substitute for a well-made, wood-fired pizza, but certainly not awful. It's made fresh (the crust starts as flour and water). Its great virtue is that it operates 24 hours a day, so if you have the midnight munchies, it will be available. The article notes that this pizza is aligned to Romans' (rather than Neapolitans') taste, having a relatively crispy crust. That is not my preference, but I think this is something I'm going to need to try out on my next trip to Rome.
The machine is at Via Catania 2, about 3/4 mile west of Tiburtina Station and just under 1-1/2 miles northeast of Termini Station. Google says public transit can get you from Termini to the vending machine in about 15 minutes. The area is described as residential and located between a university and a hospital, both providing a lot of potential late-night customers.