If you are visiting Barcelona for the first time, you cannot beat this location. This apartment is in the Examples neighborhood and is very centric to Gaudí houses, Lá Sagrada Família, the gothic quarter, the beach, and La Ramblas.
You will stay on the 6th floor and have a working elevator - so don’t worry about lugging your baggage all the way up to the top.
The Wi-Fi works great. I spent 2 weeks in the apartment working from “home” and the Wi-Fi speeds were as fast as 75 Mbps and as slow as 30 Mbps for download speeds and had upload speeds between 8 Mbps and 25 Mbps.
You are also located right across the street from the Gràcia neighborhood, which is my favorite area in Barcelona. Tons of restaurants and bars just down the street.