There are things that might worry you in the beginning, but you get to like it throughout the stay.
Location. Parallel is an ugly street with pretty much nothing on it, but if you explore the neighbourhood you'll find great coffee (Syra, The coffee, paradero), groceries (Amettler origin, St Antoni market), fitness (Viva gym), coworking (Co Co office) etc. The underground is 2min walk and the Catalunya is 5 minutes ride.
The apartment has large light windows, nice kitchen to cook on, an A/C in every room, great TVs and comfortable bed in the main bedroom. On the other hand, the other room felt like a prisoner's cage and the bathroom was horribly tiny and didn't fit into the overall apartment's design. Wi-fi was incredibly slow.
Washer+dryer is in the building, it might seem rather uncomfortable to share with other people, but there weren't many during our stay.
P.s. You have to make a deposit, but it will be returned to you upon checkout or next day