We had a great time at Xavi & Victoria's apartment. The room is very clean and the bed is very comfortable. Although there is no window in the room, we were able to air out the room during the day and keep ourselves cool at night using the fan they provide us.
The apartment is very centrally located! If you want, you can walk almost anywhere (we walked to the beach!) or you can take the nearby metro! There are a lot of great restaurants and bars nearby, and Xavi lays them out easily for you in his homemade guidebook!
I highly recommend that you stay with Xavi if you are in Barcelona! The location is perfect, the bed is comfortable, and the hosts add a homey touch to your stay that is invaluable!