We had a great time at Arne's place! Check-in was easy and the host was in constant, prompt communication.
The building is in a central, safe location for walking around the city. It is a short distance from the Gracia and Eixample districts where you will find a variety of great restaurants and bars. If you plan on eating at the apartment, there are two grocery stores and a great coffee shop that opens early (& does take-out) nearby.
The apartment is sunny, clean, large and the beds were comfortable. The air conditioning worked well enough and it was pretty quiet (for a city) if you shut the windows at night. It got the job done, but was not above expectations. It's in need of some basic maintenance (wobbly doorknobs, the main shower drains slowly, etc) and the second bathroom is extremely small to the point that it's almost unusable.
Overall a great place to stay if you value location, safety, and space.