We actually got another apartment which was huge and right in the heart of the party district with two balconies above the partying crowd. It was a bit noisy but we really enjoyed it, and there were three (!) double rooms in the back of the apartment which were quiet for those who needed rest. The bathrooms were a little small, and the place is hardly accessible by car, but that's true for the whole Barrio Alto.
All in all we had a great experience and a lot of fun. Absolutely recommended.