I stayed in the apartment for a month.
Pros:
- best location in Rio
- great wifi, I haven't had any problems with internet at any time
- apartment is small, but has everything you might need, except a washing machine (there is a cheap laudromat a couple of blocks away)
cons:
- not enough light through the windows, so the apartment is a bit dark
- shower is not warm enough on cold days (but that's definitely not an issue december-march)
All in all, I probably wouldn't stay again for a month (apartment's too small) but for a week or so it is perfect.