Mirko's apartment is a good space that would be a great rental for several people for a week or so. For a couple of people only in Rome for a couple of days, for the price I wished I had stayed closer to the sites - it was 40 minutes on public transport to the Vatican and Colosseum, though only about 10 by cab if that's how you want to do it.
As far as the apartment itself, it's a good space with 2 nice balconies and separate air conditioning in the living and bedroom. The bed was pretty comfortable and there were clean linens and towels available.
The downsides were some cleanliness-related: while the space was very neat, there's quite a bit of mold in the shower (which is small, and so kind of gross to bump into when showering) and some in the kitchen as well. There was also some food bits on the couch from the previous residents when we arrived. The one time we tried to use the kitchen, to boil water, the water boiled up very cloudy, so I assume the pot was dirty. The floor of the apartment made my feet turn black a bit, and when I spilled some water, it was clear in cleaning it that it hadn't been swept/mopped in a while.
A small bit of plaster fell down from the bathroom ceiling as we were trying to pack the last night, I messaged both Mirko and his helper who had checked us in, but neither responded on this and it took a while to find the broom hiding on the balcony.
There's also a weird note about turning off the water boiler when leaving- but no indication as to how to do this and Mirko's helper didn't fill us in.
Overall, it's still a space I would recommend for 4 people who would be in Rome for more than the main sites, and who aren't too finicky about cleanliness.