Pros: Very spacious common areas, tons of natural light (rare in Barcelona!), modern and secure building with elevator, quiet neighborhood that's not touristy at all (if that's what you're looking for), and giant roof deck.
Cons: (#1) The listing says the apartment has air conditioning, that is not fully accurate. There is no central air. They do have 2 wall-mounted fans in the common areas, but nothing in the bedrooms. We were here in October when it's cooler, and the bedrooms were still 80+ degrees. They provided fans, but obviously those don't create cool air. We were able to live with this, but the listing needs to be revised for accuracy. (#2) The house rules say that you will have to sign a contract and pay an additional deposit to stay here, but before booking you should be aware that the contract is in Spanish (it made me very uncomfortable to sign a legal contract in a foreign language), and the deposit is paid off Airbnb's platform (hosts are not supposed to do this).
The pros outweighed the cons, but I would strongly encourage the host to update their listing to reflect what I mentioned above so that guests are not surprised.