We recently stayed at Marco's beautiful apartment for over a week. The place is exactly how we saw it on the photos. Very clean and well kept. The mattress size and quality is very good. Lots of pillows, clean bed sheets, towels and toiletries. Although the kitchen is well equipped, we didn't get to use it much as we mostly eat out. As for the location, it's literally 7 minutes walk away from St-Peter's and 5 minutes from the train station or bus stand (we usually took bus #64).
Marco is an excellent host. Even though we didn't get to meet him in person, we communicated with him via email. When we needed coat hungers, iron and iron board, we sent him an email and the following day he dropped them off at the place. This, regardless of the fact that these items were not listed under "amenities" being provided by the host (which we failed to notice when we booked the place).
All in all, we enjoyed our stay at Marco's and would do it again in a heartbeat. Highly recommended.