We were delighted with the apartment. It was exactly as it is described and shown in the pictures, in a mostly quiet neighborhood with a supermarket and pharmacy 2 minutes away, in a clean building. The apartment is equally clean and well maintained, with plenty of sunlight and a balcony, and also really well equipped with everything you might need (iron/ ironing board, hair dryer, kitchen utensils, etc)
Its location is extremely strategic, as you are right next to the Flaminio metro station which can take you absolutely anywhere (also important for when you're arriving from/ to the airport) in minutes, but even if you don't want to use the metro, you can also walk to many of the sights (Piazza del Popolo and Villa Borghese are 4 minutes away, the Spanish Steps, Fontana di Trevi and Castel Sant'Angelo have a bit more distance but still very walkable, and for everything else you can use a combination of walking and metro/ bus)
Check in and check out were both simple, Alberto himself met us at the apartment for the check in and you can discuss your options for check out with him directly. He could've been a bit more talkative in his messages prior to our arrival but that was more of a personal preference than a real problem. He also sent us a link to a "guest app" that included a lot of useful information, like detailed instructions on how to get to the apartment from the airport, which really helped us.
Also, important: Italy's city tax is *included* in the price for this apartment, so the final price is exactly what you'll be paying, while other hosts will be asking for more money later and you'll end up over budget.
All in all, we were very happy with our choice, we'd love to visit again, and we highly recommend it. Grazie mille, Alberto!