I stayed with Michael for approximately 6 weeks and had a lovely stay. The apartment is very suitable for longer stays with plenty of linen, a washing machine and an adequate kitchen. The back patio is very spacious with an excellent view that lets you enjoy the sunsets at dusk and lots of green plants to make you feel comfortable during the day. The location is very good. There are cheap gyms and supermarket within walking distance (10-15 minutes) and a small store for daily needs about 3 minutes away. If you're coming to Rio only to enjoy the beach you might find it better to locate closer, but Michael's apartment is, in my genuine opinion, located in a far more interesting area of Rio. Santa Teresa is fantastic. It's beautiful and artistic and filled with some very bohemian cafes and bars. There is a lot of great music in the area as well. It's just so much more interesting and cultural than being in areas like Copacabana and Ipanema. Lapa is an easy walk away as well for those who enjoy a lively bar and club scene. Also, taxis and ubers are cheap and easy to arrange from the apartment, making the beach convenient enough to reach. The subway isn't far away either if you'd prefer to travel as cheaply as possible.
Michael communicates exceptionally and makes sure your arrival goes very smoothly. He's very helpful with anything and really attentive to any of your needs. He pays attention to the small things - making sure you have enough towels or sheets if you're staying longer; providing metro cards that you can add money to so that travel by bus and metro is easier; leaving you tourist information that you can look through to get a better sense of Rio. He's really an excellent host. I highly recommend staying with him.
It's true that there are some stairs that you'll have to climb, so it might be a bit problematic for anyone with physical difficulties. Otherwise, you might sweat a bit but it's not so difficult. I regularly walked around at night and did not find it to be unsafe.