We visited Rome in January, and when we arrived quite late at the apartment, it was freezing cold in there. The heat had been turned off for at least several days and it was about 15-16°C in there. When we had a call with Ludovica about this she was incredibly rude, told us to wait 20 min after the heat had been on (had been blasting at full power for 40min by that time), that it should be fine. Of course it wasn't, even the next morning it was still cold, especially in the bathrooms (about 18°C), it took almost 24h for it to actually be pleasant. It gave our trip a very unpleasant beginning.
Other than that, the apartment itself was lovely and clean, beds were comfortable. All the main sights are walkable.
If you visit in the winter just make sure to ask them to turn the heat on a day in advance.