The location is extremely central, there are endless restaurants and bars in only 5 minutes walking distance. There is a large supermarket and train/metro station in 2 mins walking distance. The kitchen is well equipped, I haven't missed anything, the knives were very blunt however. General condition of the apartment is ok, but is definitely not as good as seen on photos.
The apartment is located on Rambla which is one of the dirtiest and sketchiest places in the center of Barcelona. People are selling drugs 20 m from the front door. It is also loud until late at night and you can feel the vibrations of metro trains. The internet connection was unstable mostly. These factors makes this apartment not suitable for work or longer stays in my opinion.
Then the house rules. You must check if everything works in first 24 h of stay. If something turns out to be broken, you can be held accountable. An additional person (3 max) will cost 20 € per night. There is an extra fee for electricity.