This is the third time I have used Airbnb. The first experience set a very high bar, and the second one did manage to give the first one a very fair fight. The current experience I have had, unfortunately, did not meet the same standards.
The room is quite spacious for a single traveler, with lots of storing space (some of which tends to fall apart). Unfortunately, the room overlooks a main avenue (Avenida de Roma), which makes it quite noisy at times, even with the windows closed. I didn't mind that too much, but it should be taken into consideration.
The shower is not easy to handle. The shower door is not wide enough nor tall enough to hold all the water inside,. The water current is very weak, and takes a long time to heat up.
There is a rather unpleasant odor in the toilet area at times.
As for the hostess:
Her communication skills leave a lot to be desired. She claims to speak English, but her fluency in the language is rather limited. When we corresponded before my arrival, she insisted on using Portuguese, even after I stated the obvious, that I do not speak the language. I thought it was her rather strange sense of humor, but when she persisted, I was beginning to feel more like the butt of the joke.
All in all, I don't think we exchanged more than 50 words during my 8-day stay. She spent most of the time in her room, and didn't make any attempt to communicate with me, not even checking if everything was OK or if I needed anything. I imagine some travelers would consider this an advantage. But for me, one of the big upsides of using Airbnb is getting to know local people, spending time with "real" people, as opposed to hotel & resort personnel.
Bottom lines:
Pluses:
Spacious, affordable room, within easy access to public transportation to the city center, and close to useful shops (groceries, mainly);
Minuses:
Rather frugal conditions.
And if you are looking for a friendly, welcoming and communicative host, one that can give you useful tips and exchange interesting insights with you - look elsewhere.