My family of four (2 adults, 2 kids) stayed here for one night before flying out of Rome. As others have pointed out, this is an apartment managed by a company, not an individual. That's actually a good thing, for the company is in the building and - as I happily found out - on call even in the evening. We were missing sheets for the pullout sofa, and despite the fact it was late at night, someone came up and helped us out. They also setup airport transportation for us.
As for the apartment, it's very basic. Just a few pieces of furniture and a kitchen with few cups and dishes. It's clear no one actually lives here, for there are no personal affects or decorations anywhere. Not exactly cozy, but it does the job.
Proximity wise, it's in the center of everything. 20 minute walk to the Colosseum in the south, 10-15 minute walk to the Pantheon and other sites in the west.
We communicated with the host company via WhatsApp, and found them to be very helpful and responsive.
Great spot for a group if you need something simple and easy without a lot of frill.