AMAZING location. So many restaurants within reach, with great Indian food, an empanada place, and some fantastic cafes within steps of the front door. Grocery store not too far away either.
It is on the 4th floor, and the elevator is small, but we were able to fit our rental road bikes in (one person + bike at a time). The street below can be a little loud (we were there during the La Castanada festival after Halloween) so wouldn't pick this place if you go to bed early - but that's not why you go to Spain!
The apt itself is really nicely furnished, and feels like a home - spice cabinet and coffee pods included. The bed is nice, comfortable for two people, but never tried the pullout couch. Bathroom was nice too, but a little weird with the mostly-glass door. Make sure you're close with your travel companion(s)! Having a washing machine in the apartment was nice, and Cesc provided us with laundry detergent and all the cleaning supplies we needed.
Really liked this place. We were here only 4 days, but could have stayed for two weeks!