We really enjoyed our stay at Joan's apartment.
I loved the clean, contemporary decor, and we couldn't have picked a better neighborhood! It's quaint and much quieter than staying downtown, but still close enough to walk or take public transit to just about any attraction. The balconies, rain shower, and washing machine were very nice.
Note that the unit is on the sixth floor; it was no problem for us, but it could be an issue for older guests or kids. Also, there is a small tax you need to pay on arrival - that applies to any Airbnb in Barcelona, but it's good to know ahead of time.