I highly recommend Paulo Ceasar's apartment. Here's what stood out:
Number one, he's a great guy. He's intelligent and educated and doesn't treat you like a customer, but rather as a guest and as a new friend. He was even kind enough to invite me out with a group of his friends to a music venue in Lapa.
Also, the fact that he himself lives on the same floor was a bonus. While I was there, there was, unfortunately, a problem with the air conditioner being unusually noisy. He was conscientious enough to have his repairman come three separate times, the third of which finally fixed it (a bit too late for me, unfortunately, but good for whoever will be his next guest).
The amenity that I appreciated the most was a very comfortable high-quality mattress. He mentioned that this mattress was the same one that he bought for his own apartment.