We spent 5 days in Marks apartment, and we can safely recommend staying in this location! Very safe and cozy neighborhood, and the building and apartment were both very clean and well cared for. The apartment is very stylish and modern, with 2 full baths with huge rainfall showerheads. Very high ceilings, with a comfortable heating system (we were there in January). Kitchen was well equipped with the most common staples, and I enjoyed Nespresso coffee each morning. The neighborhood is in a very central location, but in a quiet street. Easy access to close-by grocery stores. About 5 minute walk from the Tiber, it is easy to get to most sights by walking.
Mark is an attentive host, and answered quickly if we had any questions. The self check-in worked great, very good descriptions on how to do everything!
Would love to stay there again next time we return to Rome!