Artur met us as the appointed time and helped us up to the apartment. It is everything the listing says, and more. The photos don't really reflect how close you are to the Sagrada. It loomed large from the balcony where we ate and sat whenever we could.
The apartment had everything we needed to be self-sufficient, and is secure. Artur gave us fantastic local information and a map which he marked for us.
We were a bit worried about pick-pockets but Artur gave us good advice about getting around and general bag-care.
Tip 1 : don't be worried about using the metro - it is very clean, well lit, well signposted, and easy to use to get around quickly, just take care with your bag as you would anywhere.
Tip 2: visit Hospital de Sant Pau. Not many people visit, but it was built by Gaudi's teacher and is beautiful. We also recommend the Context Tour that covers this and the outside of the Sagrada.