This place is GREAT - the view is absolutely worth staying here. This is a very well located apartment so its great for sight seeing, but beyond that we would stay here just for the view itself. For all 8 mornings we stayed here we woke up, smiled at the Duomo, and said goodnight to the Duomo before we went to bed. It's just gorgeous! The apartment is very spacious for two adults, and very do-able for 3-4 as well if you are not picky about having less space to "expand your suitcase" and sleeping on a pull out sofa. In fact, one of us slept on the pull out sofa for 3 nights just because it was so comfortable!!! Highly recommend! The Air conditioning is extremely quiet - my partner cannot sleep with the AC or heater running at home but he managed just fine all 8 nights in this apartment. It's basically silent, and no street noise in the apartment that we noticed.
Other reviewers already pointed out there are a lot of stairs. It is not for people with low mobility, but as long as you can carry your stuff up once and down once... you are good to go! Our host was very flexible with check-in and helped us get our bags stored since our transatlantic flight came in around 11am. All around recommend this place!