First, the apartment itself and the location are perfect. It's a pedestrian friendly street with lots of cafes and great vibe. Apartment is excellent.
However, our check-in experience was terrible. We arranged to meet at the apartment after our train arrival time. It was already dark outside and 40 degrees F and we had several suitcases. Marco was in another country on vacation so a friend was meeting us. He didn't arrive. Marco and I texted and two other friends of his came to meet us. When the friends finally arrived (90 minutes after we should have been met by the first friend) they didn't have the right keys to this apartment, but an adjacent one. They broke into the correct apartment via a hidden doorway using a kitchen knife while we waited. Two hours after arrival, we made it into the apartment. Standing in the dark on a street for 2 hours? Not great.
Marco offered to pay our return taxi trip to the airport as an apology.
We also didn't have power our final morning in Rome. In Italy, you sometimes need to flip switches on the circuit breaker to get the power back on. We couldn't locate it (it's hidden under a portrait on the wall, we found out after departure) so we had to pack by iPhone flashlight. It was not Marco's fault but please do locate the circuit breaker box so you know where it is! Much easier to find in a well-lit apartment than at 4:30 AM in the dark!
All in all, the apartment is wonderful. The check-in was not. I hope it is a fluke and he is generally more responsive. I'd like to believe that this was just a big mistake.