This apartment is really spacious - we were four people and didn't feel like we were on top of one another at all during our stay. With more people it might have been a bit tricky using the one bathroom to get ready each morning, so if you're more than 3-4 people, do consider that.
The apartment had everything we needed, and the hosts had left various toiletries/kitchen items from previous guests which was handy for things we'd forgotten to pack!
While the apartment was generally clean, some of the bedding had old stains on it (it had clearly been washed, but we found this a little off putting and spent the first day re-washing and drying these.)
This was the only negative.
The location is good, 10 minutes walking from the Colosseum and in walking distance of the central station. There are trams and buses 5 minutes away to get to other parts of the city.
Other reviews mentioned it being noisy at the front, but we didn't find this much of a problem in January.