I'm in Copacabana for over a month, attending an intensive Portuguese school. I needed an apartment that was located close to the school, the beach, the gym, the Metrô, and with markets and restaurants nearby. This apartment checked off all of the boxes.
It's a one bedroom, one bath condo located on a higher floor in a building that has two elevators to service it. The bed is set up as a queen sized bed but it consists of two single beds pushed together, so two friends could also stay here comfortably.
Given the length of my stay, I brought a ton of clothes, personal care items, and gadgets with me and the closet space was able to accommodate everything. There is a night stand and a good sized desk close to electrical outlets for charging your electronics. The bedroom has air-conditioning and it cools the bedroom sufficiently at night.
The kitchen has a two automatic burner gas range, refrigerator/freezer, sink, microwave, and several other electrical appliances, e.g., blender, sandwich press, and toaster. It comes well equipped with pots and pans, dishware, and utensils. There are two bar stools at the kitchen counter and a small table with two chairs in the living area. There is also a combo clothes washer and dryer in the kitchen.
The living room has a nice LED TV and there is NET TV service with over a hundred video broadcast channels, although not CNN International, and dozens of music channels containing practically every genre. The TV does have open HDMI ports, so you could watch the nightly PBS Evening NewsHour live or taped on YouTube, using either an HDMI cable from the TV to your device or a Chromecast. There is a sofa in the living room although it is not a sofa bed.
While the living room and kitchen are not air-conditioned, there is a large bidirectional ceiling fan in the living room that circulates air nicely. Also, there are windows on both ends of the "railroad car" style apartment. These may be opened to catch a cross-ventilation breeze.
The small bathroom has a sink and standup shower but no tub. The shower head delivers hot water from a heater in the kitchen within 30 seconds or so. There is a toilet but it does not have a bidet nozzle and there is no separate bidet.
There are two markets, a Zona Sul (kind of like a small Safeway) and a Hortifruti (a Brazilian version of Whole Foods) right around the corner. I haven't had a chance to explore nearby restaurants yet but Google Maps indicates that there are many. Banks, laundries, and post office are also within a short distance. And the beach at Copacabana Posto 4 is just 2.5 blocks away.
The owner, Antônio, and his partner were very nice and accommodating. My flight arrived later than expected and they were very gracious in being present for my 4-hour delayed arrival at night. They spent over an hour with me showing me all of the details of the apartment and answering my questions. Antônio has even written up a guest guidebook to the apartment, complete with instructions on how to operate several of the electrical devices in the unit. In the lead up to renting this condo, Antônio was always available to answer any questions I had, usually within minutes.
In summary, I highly recommend this apartment as a convenient and comfortable choice for 1-2 guests. I think that this apartment and its location would work for vacationers, mature students, and even business people requiring longer stay accommodations in a safe neighborhood in Rio de Janeiro.