Location: 10/10. Not much else to say here, the central location and proximity to La Sagrada Familia are unbeatable.
Host: 10/10. The company is easy to communicate with, they offer transportation t/from the airport for an extra charge, and the driver Carlos is extremely helpful and nice. Checking in and getting in/out of the building is easy.
The apartment: 5/10. The issues are: There are no napkins/paper towels, no food basics except salt, no drying rack for dishes, which was difficult to work with after eating. There was a (leaky) clothes iron but no board. The floors were in need of a good sweep and perhaps a wash too. The shower had unpredictable hot water, usually about 30 seconds worth but sometimes none. Wi-fi is shared in the building and sporadic. One room smelled as if it has had some water damage.
Overall: 7/10. A great place to stay if you are not going to be spending a ton of time in the apartment.