Roman's flat was perfect for my stay of 2 weeks in Prague. It's in a quiet area, although there's one bar across the street if you'd like to have a cocktail close to home in the evening. I kept the windows open often and it felt very safe. It's just a few blocks to the beautiful river, and I walked all over Prague, though the tram system is easy to navigate and free. Roman answered all my questions quickly, he gave me the mail key when my workplace sent something to me in the mail, and he reassured me on etiquette in Prague (and for AirBnB).
One caveat: It wasn't a problem for me, but I can see it being difficult for some people to climb the circular staircase 4 floors with luggage or groceries.
Otherwise, perfect stay and would definitely come again.