The location of the apartment is wonderful. I fell in love with the Gothic Quarter and would recommend the neighborhood to anyone visiting Barcelona! Overall we had a great stay at Reyes's place and loved the bars and coffee shop that are right below the apartment.
It should be noted that you need to walk through the secondary bedroom and the master bathroom in order to reach the master bedroom. The apartment is essentially one long hallway. This works for most people and for us was OK, but wasn't the greatest set-up given that we were traveling with my mom and sister.
The apartment is also rather dark, as not much daylight enters the one window up front. However, I'd assume this is the case for most places in the Gothic Quarter, and that if anything, this apartment is probably better than most (just far less than what I'm used to or prefer).
The apartment's wifi was not working for the first two days of our trip, and we found that with the thick brick walls and ceiling we also had no cell or data service inside the apartment.
Make sure you're aware of the fact that this listing charges a fee for late arrivals, and that the fee will increase the later you get. We had a flight delay and then ended up waiting over an hour for our luggage to arrive (travel headaches, ugh) which was amplified by the fact that we were incurring a larger and larger late fee on the airbnb. Understandable, of course, but if that sort of things stresses you our, avoid it (I plan to in the future).