I pretty much only have good things to say about Priscilla's apartment. In fact, even though I had to change to a different apartment for a week or so, I have already booked a return stay.
Priscilla is a wonderful host - the actual owner of the apartment - and provides a personal touch by welcoming you at check-in and answering any questions you may have about the flat, things to do nearby, etc, in an always-friendly manner. The bottles of water in the refrigerator, fruits, and basics (olive oil/salt/pepper/herbs) in the kitchen were nice touches as well.
As for the apartment itself, it is exactly as shown in the pictures. Very cosy, well-illuminated with (nearly) floor-to-ceiling windows in the living room, comfortable air conditioning, and thoughtful design touches such as 'mood lighting' in the living room, a modern bathroom with white stones, beach games (raquets & ball etc), cool books with historical photos of Rio, etc that make the apartment truly charming and chic. The kitchen is small but has everything you need to cook some meals at home (including a blender).
The location of the flat, with easy access to both Ipanema and Copacabana, cannot get any better. The beach is a few minutes away, a great Zona Sul grocery store for all your needs is one block away, and Ipanema nightlife is a within a stone's throw.
A word of caution for light sleepers: the street outside can be noisy both during the day and at night, given that the flat is on the 2nd floor. Frankly I think this is likely going to be the case anywhere you stay in Ipanema unless you are on a very high floor, and it did not bother me much.