Marco is a nice host and was always responsive. He gives you a good orientation the day of check-in and was always available via Whatsapp, text or phone to answer questions, give us suggestions etc. We were in constant touch over Whatsapp.
The apartment comfy, and the heating and the hot water were excellent (both quite important for us). It's a bit away from the city center, but right in front of a bus stop (Aurelia- Da Rosate), so as long as you can figure out the byzantine Roma public transportation system (which took us about 2 days to master - Google Maps FTW!), you are golden and about an hour away from the city center (Colosseo, Foro Romano etc.)
This said, we did face 2 issues which I feel I should mention for the sake of future guests:
1) Water - the water in the apartment had a heavy limestone taste and smell which made it undrinkable for us. Maybe others might be able to (if it's an acquired taste), but we couldn't. This became a pain for us because we had to buy bottled water from the supermarket and lug it along to the apartment. Marco said this could be fixed by a water filter, so this might be something he would do for the future.
2) Unbeknownst to even Marco, his neighbor decided to acquire a dog (which is not allowed in the apartment building). This dog made our nights miserable because it would bark and keep loudly rattling its metal cage. This would happen at random and through the night. We notified Marco and he was furious over this, so this may no longer be an issue now.
But overall (especially if the above 2 issues are fixed), I would recommend Marco's place and it served us well in exploring Roma.