We booked the apartment shortly before going, and everything was confirmed very quickly - communication with the owner was very good. They helped with parking information as well. When we arrived (a lot later than first expected), we found an abundance of information on the dining room table. This included information about the apartment (codes and rules), about the local area, restaurant recommendations on a map of the city, an offer through an agreement with a café down the street (€5 for a very simple breakfast - not to our liking unfortunately, but nice nonetheless), WiFi networks and passwords, and maps of the city.
They had even set up a baby crib for our infant daughter, though this was not requested from our end, and neither was it necessary - this was still very impressive and welcoming.

Because we arrived at a late hour, our contact had left and decided on a time for us to meet the day after - she showed up 20 minutes earlier, as I was on my way out to pick up water, as my wife was getting dressed. She entered the apartment, and it was very uncomfortable for my wife and I, and my wife felt rushed to get dressed to talk. She walked us through the map (very quickly in decent English), and gave us lots of information and adviceyou about the city, including common attractions, how to get there, and suggestions as to what metro card to get - all this was greatly appreciated.
The day we were leaving, the same woman came, again earlier than agreed on, and something about the situation made it very hard not to feel rushed and uncomfortable.

The apartment is very charming, especially when waking up in the morning and peering out through the window from the bed. We were very happy with our stay, and can easily recommend this apartment to anyone going to Barcelona. Had it not been for the feeling we were left with from our contact there, this would have been an easy 5-star rating