My two friends and I have spent three nights at Joaquim's. The location is wonderful and close to the main attractions. Bairro Alto is just around the corner, so there is plenty of bars and restaurants in the surroundings.
The apartment itself was not as great as the location. It was pretty small (3 people max) and not so clean (in particular, the sofa-bed was simply dirty). Shampoo should have been included but there wasn't any. Plus, there was no fridge, which could have been useful to keep some water cool.
Check-in is not flexible, so we had to keep our luggage stored elsewhere for a while.
Overall, we would reccomend it only to young people with not so high expectations as we were :)