This appartment is perfect for four people. We were there with our two kids and we had lots of space.
Wifi and A/C worked very well.
The location is very good -- about a 10-min walk from Roma Termini, 15-min walk to the Colosseum, 5-min walk to a supermarket, 5-min walk to the metro. Note the supermarket near the appartment does not sell detergent (if you want to wash clothes) the closest that does is near Termini.
A great place for your stay in Rome!