Staying at Antonio's apartment was a breeze. He was out of town, but his sister-in-law Rosa picked us up at the airport and his friend Roberto met us at the apartment. Roberto showed us around the place and gave us a few tips for around the neighborhood.
The apartment itself is modest in square footage, but about perfect size in what you need. The high ceilings help add to the space. The bed was extremely comfortable and the bathroom was large enough with a pretty good shower.
Closing the windows helps keep out a lot of the noise, but not all of it. The general traffic noise is no big deal (outside of the occasional emergency vehicle), but revelers from the bar down the side street are harder to ignore. We didn't hear a peep from any neighbors, though, except when people were passing through the shared entryway.
The location of the apartment is outstanding. The proximity to Ramblas de las Catalunyas and Passeig de Gracia put you right in the heart of the Eixample. You can easily walk to Plaza Catalunya and the Barri Gotic, and the Passeig de Gracia metro stop is very close and connects you to pretty much any place in the city.